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+*.so
diff --git a/COPYING b/COPYING
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--- /dev/null
+++ b/COPYING
@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
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+                            Preamble
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diff --git a/COPYING.LGPL b/COPYING.LGPL
new file mode 100644
index 0000000..f6683e7
--- /dev/null
+++ b/COPYING.LGPL
@@ -0,0 +1,501 @@
+                  GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 2.1, February 1999
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+That's all there is to it!
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..d002594
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,31 @@
+include config.mk
+
+CMODULE_PREFIX		?=	cmodules
+LUAMODULE_PREFIX	?=	luamodules
+CFLAGS		 		:=	$(shell pkg-config --cflags melisma.h) -std=c11 -D_XOPEN_SOURCE=700 -D_GNU_SOURCE
+LDFLAGS		 		:=	-shared -fPIC -lm
+CMODULES	 		:=	$(CSOURCES:%.c=%.so)
+
+all: $(CMODULES)
+
+mod/sample.so: CFLAGS += $(shell pkg-config --cflags samplerate sndfile)
+mod/sample.so: LDFLAGS += $(shell pkg-config --libs samplerate sndfile)
+
+mod/%.so: mod/%.c
+	@ printf "CCLD\t%s\n" $(@)
+	@ $(CC) -o $(@) $(<) $(CFLAGS) $(LDFLAGS)
+
+install: all
+	install -Dm644 -t $(CMODULE_PREFIX)/melisma $(CMODULES)
+	install -Dm644 -t $(LUAMODULE_PREFIX)/melisma $(LUASOURCES)
+
+debug: CFLAGS += -Wno-cpp -O0 -g
+debug: all
+
+doc:
+	ldoc .
+
+clean:
+	rm -rf mod/*.so
+
+.PHONY: install clean doc
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..6a5f63e
--- /dev/null
+++ b/README.md
@@ -0,0 +1,26 @@
+# melisma-modules
+
+A collection of modules for [melisma](/melisma).
+Documentation is located [here](/melisma-modules/doc).
+
+## Building and installing
+
+Make sure melisma is installed and that melisma.h.pc is in PKG_CONFIG_PATH.
+Copy config/config.mk to the root directory.
+Edit config.mk to customize which modules will be
+built/installed. Then build and install with:
+
+```bash
+$ make install CMODULE_PREFIX=... LUAMODULE_PREFIX=...
+```
+
+Some modules may require additional system libraries.
+Which modules need which libraries should be evident from the Makefile.
+
+To make modules available for import, make sure the installation
+prefixes are in LUA_PATH and LUA_CPATH.
+
+## Licensing
+
+melisma is licensed under GPL v3 or later (see COPYING).
+ladspa.h is licensed under LGPL 2.1 or later (see COPYING.LGPL).
diff --git a/config.ld b/config.ld
new file mode 100644
index 0000000..ab7e841
--- /dev/null
+++ b/config.ld
@@ -0,0 +1,14 @@
+project = 'Melisma modules'
+title = 'Melisma modules'
+description = 'Melisma module reference'
+format = 'markdown'
+no_space_before_args = 'show'
+sort = true
+style = '!fixed'
+
+postprocess_html = function(html, module)
+    return (html:gsub(
+        '<div id="navigation">',
+        '<div id="navigation">\n<p><a href="/melisma-modules">Back to repository</a></p>',
+        1))
+end
diff --git a/config/config.mk b/config/config.mk
new file mode 100644
index 0000000..c0b14ca
--- /dev/null
+++ b/config/config.mk
@@ -0,0 +1,33 @@
+LUASOURCES := \
+	lib/distrib.lua          \
+	lib/functional.lua       \
+	lib/graphviz.lua         \
+	lib/ladspa_interface.lua \
+	lib/lazy.lua             \
+	lib/midimap.lua          \
+	lib/osc.lua              \
+	lib/util.lua             \
+
+CSOURCES := \
+	mod/biquad.c      \
+	mod/buffer.c      \
+	mod/delay.c       \
+	mod/expression.c  \
+	mod/fs.c          \
+	mod/gain.c        \
+	mod/interp.c      \
+	mod/keycallback.c \
+	mod/ladspa.c      \
+	mod/lookback.c    \
+	mod/mixer.c       \
+	mod/null.c        \
+	mod/nullsink.c    \
+	mod/oscil.c       \
+	mod/pan.c         \
+	mod/passthrough.c \
+	mod/playback.c    \
+	mod/sample.c      \
+	mod/serial.c      \
+	mod/spring.c      \
+	mod/timer.c       \
+	mod/udp.c         \
diff --git a/doc/classes/buffer.html b/doc/classes/buffer.html
new file mode 100644
index 0000000..0811641
--- /dev/null
+++ b/doc/classes/buffer.html
@@ -0,0 +1,247 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><strong>buffer</strong></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>buffer</code></h1>
+<p>Audio buffer for capture/playback.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> mbuffer = <span class="global">require</span> <span class="string">'melisma.buffer'</span>
+<span class="keyword">local</span> mevent = <span class="global">require</span> <span class="string">'melisma.event'</span>
+
+<span class="keyword">local</span> input = ...
+
+<span class="comment">-- Create a buffer with capacity of 5 seconds
+</span><span class="comment">-- Capture stops automatically when buffer is full.
+</span><span class="keyword">local</span> len = <span class="number">5</span>
+<span class="keyword">local</span> buffer = mbuffer.<span class="function-name">init</span>(input, len)
+
+<span class="comment">-- Capture audio
+</span>buffer:<span class="function-name">capture</span>()
+
+<span class="comment">-- Playback after capture 3 seconds
+</span>mevent.<span class="function-name">schedule</span>(<span class="number">3</span>, buffer.playback, buffer)
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#buffer.init">buffer.init(input, len)</a></td>
+	<td class="summary">Create an audio buffer.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#buffer:capture">buffer:capture()</a></td>
+	<td class="summary">Start capture mode.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#buffer:length">buffer:length()</a></td>
+	<td class="summary">Get length of captured audio.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#buffer:playback">buffer:playback()</a></td>
+	<td class="summary">Start playback mode.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#buffer:speed">buffer:speed(speed)</a></td>
+	<td class="summary">Set playback speed.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "buffer.init"></a>
+    <strong>buffer.init(input, len)</strong>
+    </dt>
+    <dd>
+    Create an audio buffer.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">input</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signal.
+        </li>
+        <li><span class="parameter">len</span>
+            <span class="types"><span class="type">number</span></span>
+         Buffer capacity in seconds.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/buffer.html#">buffer</a></span>
+        The newly created audio buffer.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "buffer:capture"></a>
+    <strong>buffer:capture()</strong>
+    </dt>
+    <dd>
+    Start capture mode.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "buffer:length"></a>
+    <strong>buffer:length()</strong>
+    </dt>
+    <dd>
+    Get length of captured audio.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><span class="type">number</span></span>
+        Length of captured audio in seconds.
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "buffer:playback"></a>
+    <strong>buffer:playback()</strong>
+    </dt>
+    <dd>
+    Start playback mode.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "buffer:speed"></a>
+    <strong>buffer:speed(speed)</strong>
+    </dt>
+    <dd>
+    Set playback speed.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">speed</span>
+            <span class="types"><span class="type">number</span></span>
+         Playback speed.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/delay.html b/doc/classes/delay.html
new file mode 100644
index 0000000..3a5470d
--- /dev/null
+++ b/doc/classes/delay.html
@@ -0,0 +1,270 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><strong>delay</strong></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>delay</code></h1>
+<p>Digital delay line.</p>
+<p>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#delay.init">delay.init(input)</a></td>
+	<td class="summary">Create a delay line.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#delay:delay">delay:delay(d)</a></td>
+	<td class="summary">Set delay.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#delay:feedback">delay:feedback(f)</a></td>
+	<td class="summary">Set feedback.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#delay:gain">delay:gain(g)</a></td>
+	<td class="summary">Set gain.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#delay:wetdrymix">delay:wetdrymix(wd)</a></td>
+	<td class="summary">Set wet/dry mix.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "delay.init"></a>
+    <strong>delay.init(input)</strong>
+    </dt>
+    <dd>
+    Create a delay line.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">input</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signal.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/delay.html#">delay</a></span>
+        Newly created delay line.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "delay:delay"></a>
+    <strong>delay:delay(d)</strong>
+    </dt>
+    <dd>
+    Set delay.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">d</span>
+            <span class="types"><span class="type">number</span></span>
+         delay in seconds.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/delay.html#">delay</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "delay:feedback"></a>
+    <strong>delay:feedback(f)</strong>
+    </dt>
+    <dd>
+    Set feedback.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">f</span>
+            <span class="types"><span class="type">number</span></span>
+         Feedback.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/delay.html#">delay</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "delay:gain"></a>
+    <strong>delay:gain(g)</strong>
+    </dt>
+    <dd>
+    Set gain.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">g</span>
+            <span class="types"><span class="type">number</span></span>
+         Gain (<strong>TODO</strong>: Use decibels).
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/delay.html#">delay</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "delay:wetdrymix"></a>
+    <strong>delay:wetdrymix(wd)</strong>
+    </dt>
+    <dd>
+    Set wet/dry mix.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">wd</span>
+            <span class="types"><span class="type">number</span></span>
+         Wet/dry mix.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/delay.html#">delay</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/gain.html b/doc/classes/gain.html
new file mode 100644
index 0000000..46bea50
--- /dev/null
+++ b/doc/classes/gain.html
@@ -0,0 +1,179 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><strong>gain</strong></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>gain</code></h1>
+<p>Apply gain to signals.</p>
+<p>
+
+
+<pre>
+<span class="keyword">local</span> mgain = <span class="global">require</span> <span class="string">'melisma.gain'</span>
+
+<span class="comment">-- Interprets <code>cntl</code> as decibels and applies it to <code>input</code>
+</span><span class="keyword">local</span> input = ...
+<span class="keyword">local</span> cntl = ...
+<span class="keyword">local</span> gain = mgain.<span class="function-name">db</span>(input,cntl)
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#gain.db">gain.db(input, gain)</a></td>
+	<td class="summary">Creates a decibel gain unit.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#gain.linear">gain.linear(input, gain)</a></td>
+	<td class="summary">Creates a linear gain unit.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "gain.db"></a>
+    <strong>gain.db(input, gain)</strong>
+    </dt>
+    <dd>
+    Creates a decibel gain unit.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">input</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signal.
+        </li>
+        <li><span class="parameter">gain</span>
+            <span class="types"><span class="type">number</span> or <span class="type">channel</span></span>
+         Constant gain in decibels or a controlling signal.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/gain.html#">gain</a></span>
+        The newly created gain unit.
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "gain.linear"></a>
+    <strong>gain.linear(input, gain)</strong>
+    </dt>
+    <dd>
+    Creates a linear gain unit.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">input</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signal.
+        </li>
+        <li><span class="parameter">gain</span>
+            <span class="types"><span class="type">number</span> or <span class="type">channel</span></span>
+         Constant gain or a controlling signal.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/gain.html#">gain</a></span>
+        The newly created gain unit.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/interp.html b/doc/classes/interp.html
new file mode 100644
index 0000000..cea6277
--- /dev/null
+++ b/doc/classes/interp.html
@@ -0,0 +1,322 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><strong>interp</strong></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>interp</code></h1>
+<p>Interpolation.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> minterp = <span class="global">require</span> <span class="string">'melisma.interp'</span>
+<span class="keyword">local</span> mevent = <span class="global">require</span> <span class="string">'melisma.event'</span>
+<span class="keyword">local</span> mgain = <span class="global">require</span> <span class="string">'melisma.gain'</span>
+
+<span class="keyword">local</span> interp = minterp.<span class="function-name">init</span>(<span class="number">0</span>)
+
+interp:<span class="function-name">linear</span>(<span class="number">1</span>,<span class="number">1</span>)
+
+mevent.<span class="function-name">schedule</span>(<span class="number">0.5</span>, <span class="keyword">function</span>()
+    <span class="global">print</span>(<span class="string">'current value:'</span>, interp:<span class="function-name">sample</span>())
+<span class="keyword">end</span>)
+
+<span class="keyword">local</span> sig = ...
+<span class="keyword">local</span> gain = mgain.<span class="function-name">linear</span>(sig,interp)
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#interp.init">interp.init(x0)</a></td>
+	<td class="summary">Initialize an interpolation unit.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#interp:ease_in">interp:ease_in(v, t)</a></td>
+	<td class="summary">Interpolate using ease-in interpolation.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#interp:ease_out">interp:ease_out(v, t)</a></td>
+	<td class="summary">Interpolate using ease-out interpolation.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#interp:linear">interp:linear(v, t)</a></td>
+	<td class="summary">Interpolate using linear interpolation.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#interp:sample">interp:sample()</a></td>
+	<td class="summary">Get the current value.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#interp:set">interp:set(x)</a></td>
+	<td class="summary">Set value directly.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#interp:smoothstep">interp:smoothstep(v, t)</a></td>
+	<td class="summary">Interpolate using smoothstep interpolation.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "interp.init"></a>
+    <strong>interp.init(x0)</strong>
+    </dt>
+    <dd>
+    Initialize an interpolation unit.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">x0</span>
+            <span class="types"><span class="type">number</span></span>
+         Initial value.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/interp.html#">interp</a></span>
+        The newly created interpolation unit.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "interp:ease_in"></a>
+    <strong>interp:ease_in(v, t)</strong>
+    </dt>
+    <dd>
+    Interpolate using ease-in interpolation.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">v</span>
+            <span class="types"><span class="type">number</span></span>
+         Target value.
+        </li>
+        <li><span class="parameter">t</span>
+            <span class="types"><span class="type">number</span></span>
+         Interpolation time.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "interp:ease_out"></a>
+    <strong>interp:ease_out(v, t)</strong>
+    </dt>
+    <dd>
+    Interpolate using ease-out interpolation.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">v</span>
+            <span class="types"><span class="type">number</span></span>
+         Target value.
+        </li>
+        <li><span class="parameter">t</span>
+            <span class="types"><span class="type">number</span></span>
+         Interpolation time.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "interp:linear"></a>
+    <strong>interp:linear(v, t)</strong>
+    </dt>
+    <dd>
+    Interpolate using linear interpolation.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">v</span>
+            <span class="types"><span class="type">number</span></span>
+         Target value.
+        </li>
+        <li><span class="parameter">t</span>
+            <span class="types"><span class="type">number</span></span>
+         Interpolation time.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "interp:sample"></a>
+    <strong>interp:sample()</strong>
+    </dt>
+    <dd>
+    Get the current value.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><span class="type">number</span></span>
+        The current value.
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "interp:set"></a>
+    <strong>interp:set(x)</strong>
+    </dt>
+    <dd>
+    Set value directly.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">x</span>
+            <span class="types"><span class="type">number</span></span>
+         New value.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "interp:smoothstep"></a>
+    <strong>interp:smoothstep(v, t)</strong>
+    </dt>
+    <dd>
+    Interpolate using smoothstep interpolation.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">v</span>
+            <span class="types"><span class="type">number</span></span>
+         Target value.
+        </li>
+        <li><span class="parameter">t</span>
+            <span class="types"><span class="type">number</span></span>
+         Interpolation time.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/ladspa.html b/doc/classes/ladspa.html
new file mode 100644
index 0000000..846b65b
--- /dev/null
+++ b/doc/classes/ladspa.html
@@ -0,0 +1,298 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><strong>ladspa</strong></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>ladspa</code></h1>
+<p>LADSPA plugin support.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> mladspa = <span class="global">require</span> <span class="string">'melisma.ladspa'</span>
+
+<span class="keyword">local</span> spec = <span class="string">'caps.so:Plate'</span>
+<span class="keyword">local</span> info = mladspa.<span class="function-name">info</span>(spec)
+
+<span class="global">print</span>(<span class="string">'name:'</span>,info.name)
+<span class="global">print</span>(<span class="string">'maker:'</span>,info.maker)
+
+<span class="keyword">local</span> input = ...
+<span class="keyword">local</span> plate = mladspa.<span class="global">load</span>(spec,input)
+
+plate:<span class="function-name">control</span>(<span class="number">1</span>,<span class="number">1</span>)
+
+<span class="keyword">local</span> left = plate:<span class="function-name">out</span>(<span class="number">6</span>)
+<span class="keyword">local</span> right = plate:<span class="function-name">out</span>(<span class="number">7</span>)
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#ladspa.info">ladspa.info(spec)</a></td>
+	<td class="summary">Get information about a specific plugin.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#ladspa.lib_info">ladspa.lib_info(path)</a></td>
+	<td class="summary">List plugins in the specified plugin library.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#ladspa.load">ladspa.load(spec, ...)</a></td>
+	<td class="summary">Load a ladspa plugin.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#ladspa:control">ladspa:control(i, v)</a></td>
+	<td class="summary">Set the value of an input control port.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#ladspa:out">ladspa:out(i)</a></td>
+	<td class="summary">Get the audio output port at the specified index.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "ladspa.info"></a>
+    <strong>ladspa.info(spec)</strong>
+    </dt>
+    <dd>
+    Get information about a specific plugin. </p>
+
+<p>Plugin specifications are written in the format <code>&lt;path&gt;:&lt;plugin&gt;</code>,
+where <code>&lt;path&gt;</code> is the full name of the plugin library
+(e.g. <code>caps.so</code>), and <code>&lt;plugin&gt;</code> is the name or label of the plugin.
+If <code>&lt;path&gt;</code> is not an absolute path, the library is searched for
+first in the current directory, then in <code>LADSPA_PATH</code>.</p>
+
+<p>This can be used to generate more ergonomic plugin interfaces.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">spec</span>
+            <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.4">string</a></span>
+         Plugin specification.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.6">table</a></span>
+        Plugin information.
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "ladspa.lib_info"></a>
+    <strong>ladspa.lib_info(path)</strong>
+    </dt>
+    <dd>
+    List plugins in the specified plugin library. </p>
+
+<p>If <code>path</code> is not an absolute path, the library is searched for
+first in the current directory, then in <code>LADSPA_PATH</code>.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">path</span>
+            <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.4">string</a></span>
+         Path to plugin library.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.6">table</a></span>
+        List of short plugin descriptions.
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "ladspa.load"></a>
+    <strong>ladspa.load(spec, ...)</strong>
+    </dt>
+    <dd>
+    Load a ladspa plugin. </p>
+
+<p>Input signals are connected to the plugins audio input ports in the
+order that they are declared.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">spec</span>
+            <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.4">string</a></span>
+         Plugin specification.
+        </li>
+        <li><span class="parameter">...</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signals.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "ladspa:control"></a>
+    <strong>ladspa:control(i, v)</strong>
+    </dt>
+    <dd>
+    Set the value of an input control port. </p>
+
+<p>Ports are indexed based on the order they are declared by the plugin.
+This also means the indices of control ports are not necessarily consecutive.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">i</span>
+            <span class="types"><span class="type">integer</span></span>
+         One-based port index.
+        </li>
+        <li><span class="parameter">v</span>
+            <span class="types"><span class="type">number</span></span>
+         New control port value.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "ladspa:out"></a>
+    <strong>ladspa:out(i)</strong>
+    </dt>
+    <dd>
+    Get the audio output port at the specified index. </p>
+
+<p>Ports are indexed based on the order they are declared by the plugin.
+This also means the indices of audio ports are not necessarily consecutive.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">i</span>
+            <span class="types"><span class="type">integer</span></span>
+         One-based port index.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><span class="type">channel</span></span>
+        Audio output at specified index.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/mixer.html b/doc/classes/mixer.html
new file mode 100644
index 0000000..2f8625c
--- /dev/null
+++ b/doc/classes/mixer.html
@@ -0,0 +1,139 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><strong>mixer</strong></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>mixer</code></h1>
+<p>Mix signals.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> mmixer = <span class="global">require</span> <span class="string">'melisma.mixer'</span>
+
+<span class="keyword">local</span> signals = ...
+<span class="keyword">local</span> mixer = mmixer.<span class="function-name">init</span>(<span class="global">table</span>.<span class="function-name">unpack</span>(signals))
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#mixer.init">mixer.init(...)</a></td>
+	<td class="summary">Mix input signals in to a single output signal.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "mixer.init"></a>
+    <strong>mixer.init(...)</strong>
+    </dt>
+    <dd>
+    Mix input signals in to a single output signal.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">...</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signals.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/mixer.html#">mixer</a></span>
+        The newly created mixer unit.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/nullsink.html b/doc/classes/nullsink.html
new file mode 100644
index 0000000..d8a611b
--- /dev/null
+++ b/doc/classes/nullsink.html
@@ -0,0 +1,188 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><strong>nullsink</strong></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>nullsink</code></h1>
+<p>Reference otherwise disconnected nodes.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> mnullsink = <span class="global">require</span> <span class="string">'melisma.nullsink'</span>
+<span class="keyword">local</span> minterp = <span class="global">require</span> <span class="string">'melisma.interp'</span>
+<span class="keyword">local</span> mevent = <span class="global">require</span> <span class="string">'melisma.event'</span>
+
+<span class="keyword">local</span> interp = minterp.<span class="function-name">init</span>(<span class="number">0</span>)
+interp:<span class="function-name">linear</span>(<span class="number">1</span>,<span class="number">60</span>)
+
+<span class="comment">-- The output of interp is disconnected.
+</span><span class="comment">-- Need to connect it to a nullsink so we
+</span><span class="comment">-- can sample it in the event callback below.
+</span><span class="keyword">local</span> nullsink = mnullsink.<span class="function-name">init</span>()
+nullsink:<span class="function-name">ref</span>(interp)
+
+mevent.<span class="function-name">schedule</span>(<span class="number">30</span>, <span class="keyword">function</span>()
+    <span class="global">print</span>(<span class="string">'current value:'</span>, interp:<span class="function-name">sample</span>())
+<span class="keyword">end</span>)
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#nullsink.init">nullsink.init()</a></td>
+	<td class="summary">Create a nullsink.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#nullsink:ref">nullsink:ref(input)</a></td>
+	<td class="summary">Connect an input signal.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "nullsink.init"></a>
+    <strong>nullsink.init()</strong>
+    </dt>
+    <dd>
+    Create a nullsink.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/nullsink.html#">nullsink</a></span>
+        The newly created nullsink.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "nullsink:ref"></a>
+    <strong>nullsink:ref(input)</strong>
+    </dt>
+    <dd>
+    Connect an input signal. </p>
+
+<p>This makes sure the input signal is processed
+even if it's not connected to anything else.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">input</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signal.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/nullsink.html#">nullsink</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/oscil.html b/doc/classes/oscil.html
new file mode 100644
index 0000000..5aea703
--- /dev/null
+++ b/doc/classes/oscil.html
@@ -0,0 +1,392 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+<li><a href="#Class_wavetable">Class wavetable </a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><strong>oscil</strong></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>oscil</code></h1>
+<p>Wavetable backed oscillators.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> moscil = <span class="global">require</span> <span class="string">'melisma.oscil'</span>
+<span class="keyword">local</span> mexpression = <span class="global">require</span> <span class="string">'melisma.expression'</span>
+
+<span class="keyword">local</span> wt = moscil.wavetable.<span class="function-name">sin</span>()
+
+<span class="comment">-- Make an LFO for controlling the frequency.
+</span><span class="keyword">local</span> lfo_oscil = moscil.<span class="function-name">init</span>(wt,<span class="number">1</span>,<span class="number">1</span>)
+
+<span class="comment">-- Map [-1, 1] to [440, 880]
+</span><span class="keyword">local</span> lfo = (<span class="number">440</span> + (<span class="number">1</span> + mexpression.<span class="function-name">input</span>(lfo_oscil,<span class="number">0</span>) / <span class="number">2</span>) * <span class="number">440</span>):<span class="function-name">build</span>()
+
+<span class="keyword">local</span> oscil = moscil.<span class="function-name">init</span>(wt,<span class="number">0</span>,<span class="number">0.5</span>)
+oscil:<span class="function-name">mapf</span>(lfo)
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#oscil.init">oscil.init(wt, freq, amp)</a></td>
+	<td class="summary">Initialize an oscillator.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#oscil:mapa">oscil:mapa(sig)</a></td>
+	<td class="summary">Map a signal to the amplitude.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#oscil:mapf">oscil:mapf(sig)</a></td>
+	<td class="summary">Map a signal to the frequency.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#oscil:sample">oscil:sample()</a></td>
+	<td class="summary">Get the current oscillator value.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#oscil:seta">oscil:seta(amp)</a></td>
+	<td class="summary">Set oscillator amplitude.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#oscil:setf">oscil:setf(freq)</a></td>
+	<td class="summary">Set oscillator frequency.</td>
+	</tr>
+</table>
+<h2><a href="#Class_wavetable">Class wavetable </a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#wavetable.saw">wavetable.saw()</a></td>
+	<td class="summary">Saw wave.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#wavetable.sin">wavetable.sin()</a></td>
+	<td class="summary">Sine wave.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#wavetable.square">wavetable.square()</a></td>
+	<td class="summary">Square wave.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "oscil.init"></a>
+    <strong>oscil.init(wt, freq, amp)</strong>
+    </dt>
+    <dd>
+    Initialize an oscillator.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">wt</span>
+            <span class="types"><a class="type" href="../classes/oscil.html#wavetable">wavetable</a></span>
+
+
+
+        </li>
+        <li><span class="parameter">freq</span>
+            <span class="types"><span class="type">number</span></span>
+
+
+
+        </li>
+        <li><span class="parameter">amp</span>
+            <span class="types"><span class="type">number</span></span>
+
+
+
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/oscil.html#">oscil</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "oscil:mapa"></a>
+    <strong>oscil:mapa(sig)</strong>
+    </dt>
+    <dd>
+    Map a signal to the amplitude.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">sig</span>
+            <span class="types"><span class="type">channel</span></span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "oscil:mapf"></a>
+    <strong>oscil:mapf(sig)</strong>
+    </dt>
+    <dd>
+    Map a signal to the frequency.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">sig</span>
+            <span class="types"><span class="type">channel</span></span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "oscil:sample"></a>
+    <strong>oscil:sample()</strong>
+    </dt>
+    <dd>
+    Get the current oscillator value.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><span class="type">number</span></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "oscil:seta"></a>
+    <strong>oscil:seta(amp)</strong>
+    </dt>
+    <dd>
+    Set oscillator amplitude.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">amp</span>
+            <span class="types"><span class="type">number</span></span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "oscil:setf"></a>
+    <strong>oscil:setf(freq)</strong>
+    </dt>
+    <dd>
+    Set oscillator frequency.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">freq</span>
+            <span class="types"><span class="type">number</span></span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Class_wavetable"></a>Class wavetable </h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "wavetable.saw"></a>
+    <strong>wavetable.saw()</strong>
+    </dt>
+    <dd>
+    Saw wave.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/oscil.html#wavetable">wavetable</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "wavetable.sin"></a>
+    <strong>wavetable.sin()</strong>
+    </dt>
+    <dd>
+    Sine wave.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/oscil.html#wavetable">wavetable</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "wavetable.square"></a>
+    <strong>wavetable.square()</strong>
+    </dt>
+    <dd>
+    Square wave.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/oscil.html#wavetable">wavetable</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/pan.html b/doc/classes/pan.html
new file mode 100644
index 0000000..1728b7c
--- /dev/null
+++ b/doc/classes/pan.html
@@ -0,0 +1,240 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><strong>pan</strong></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>pan</code></h1>
+<p>Panning</p>
+<p>
+
+<pre>
+<span class="keyword">local</span> mpan = <span class="global">require</span> <span class="string">'melisma.pan'</span>
+<span class="keyword">local</span> mexpression = <span class="global">require</span> <span class="string">'melisma.expression'</span>
+<span class="keyword">local</span> moscil = <span class="global">require</span> <span class="string">'melisma.oscil'</span>
+
+<span class="keyword">local</span> wt = moscil.wavetable.<span class="function-name">sin</span>()
+<span class="keyword">local</span> lfo_oscil = moscil.<span class="function-name">init</span>(wt,<span class="number">1</span>,<span class="number">1</span>)
+<span class="keyword">local</span> lfo = (<span class="number">1</span> + mexpression.<span class="function-name">input</span>(lfo_oscil,<span class="number">0</span>) / <span class="number">2</span>):<span class="function-name">build</span>()
+
+<span class="keyword">local</span> oscil = moscil.<span class="function-name">init</span>(wt,<span class="number">440</span>,<span class="number">0.5</span>)
+<span class="keyword">local</span> pan = mpan.<span class="function-name">init</span>(lfo,oscil)
+
+<span class="keyword">local</span> left = pan:<span class="function-name">left</span>()
+<span class="keyword">local</span> right = pan:<span class="function-name">right</span>()
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#pan.init">pan.init(x, sig)</a></td>
+	<td class="summary">Initialize a panning unit.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#pan:left">pan:left()</a></td>
+	<td class="summary">Get the left output signal.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#pan:right">pan:right()</a></td>
+	<td class="summary">Get the right output signal.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#pan:set">pan:set(x)</a></td>
+	<td class="summary">Set the panning value.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "pan.init"></a>
+    <strong>pan.init(x, sig)</strong>
+    </dt>
+    <dd>
+    Initialize a panning unit. </p>
+
+<p>A panning value ranges from 0 to 1, where a value of 0
+will pan everything to the left.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">x</span>
+            <span class="types"><span class="type">number</span> or <span class="type">channel</span></span>
+         Constant pan or a controlling signal.
+        </li>
+        <li><span class="parameter">sig</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signal.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/pan.html#">pan</a></span>
+        The newly created panning unit.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "pan:left"></a>
+    <strong>pan:left()</strong>
+    </dt>
+    <dd>
+    Get the left output signal.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><span class="type">channel</span></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "pan:right"></a>
+    <strong>pan:right()</strong>
+    </dt>
+    <dd>
+    Get the right output signal.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><span class="type">channel</span></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "pan:set"></a>
+    <strong>pan:set(x)</strong>
+    </dt>
+    <dd>
+    Set the panning value.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">x</span>
+            <span class="types"><span class="type">number</span></span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/playback.html b/doc/classes/playback.html
new file mode 100644
index 0000000..fcee0d6
--- /dev/null
+++ b/doc/classes/playback.html
@@ -0,0 +1,331 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><strong>playback</strong></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>playback</code></h1>
+<p>Audio sample playback.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> msample = <span class="global">require</span> <span class="string">'melisma.sample'</span>
+<span class="keyword">local</span> mplayback = <span class="global">require</span> <span class="string">'melisma.playback'</span>
+
+<span class="keyword">local</span> sample = msample.<span class="global">load</span>(<span class="string">'sample.wav'</span>)
+<span class="keyword">local</span> playb = mplayback.<span class="function-name">init</span>(sample)
+
+playb:<span class="function-name">loop</span>(<span class="keyword">true</span>)
+playb:<span class="function-name">spped</span>(<span class="number">2</span>)
+playb:<span class="function-name">play</span>()
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#playback.init">playback.init(smp)</a></td>
+	<td class="summary">Intialize a playback unit.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#playback:loop">playback:loop(b)</a></td>
+	<td class="summary">Enable/disable automatic looping.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#playback:pause">playback:pause()</a></td>
+	<td class="summary">Pause playback.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#playback:phase">playback:phase(x)</a></td>
+	<td class="summary">Set playback phase.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#playback:play">playback:play()</a></td>
+	<td class="summary">Start playback.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#playback:reset">playback:reset()</a></td>
+	<td class="summary">Reset playback.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#playback:reset">playback:reset()</a></td>
+	<td class="summary">Set playback speed.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#playback:set_sample">playback:set_sample(smp)</a></td>
+	<td class="summary">Set playback sample.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#playback:stop">playback:stop()</a></td>
+	<td class="summary">Stop playback.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "playback.init"></a>
+    <strong>playback.init(smp)</strong>
+    </dt>
+    <dd>
+    Intialize a playback unit.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">smp</span>
+            <span class="types"><a class="type" href="../classes/sample.html#">sample</a> or <span class="type">nil</span></span>
+
+
+
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/playback.html#">playback</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "playback:loop"></a>
+    <strong>playback:loop(b)</strong>
+    </dt>
+    <dd>
+    Enable/disable automatic looping.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">b</span>
+            <span class="types"><span class="type">bool</span></span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "playback:pause"></a>
+    <strong>playback:pause()</strong>
+    </dt>
+    <dd>
+    Pause playback.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "playback:phase"></a>
+    <strong>playback:phase(x)</strong>
+    </dt>
+    <dd>
+    Set playback phase.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">x</span>
+            <span class="types"><span class="type">number</span></span>
+         Phase ranging from 0 to 1.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "playback:play"></a>
+    <strong>playback:play()</strong>
+    </dt>
+    <dd>
+    Start playback.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "playback:reset"></a>
+    <strong>playback:reset()</strong>
+    </dt>
+    <dd>
+    Reset playback. </p>
+
+<p>Equivalent to <a href="../classes/playback.html#playback:phase">playback.phase</a>(0).
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "playback:reset"></a>
+    <strong>playback:reset()</strong>
+    </dt>
+    <dd>
+    Set playback speed. </p>
+
+<p>A negative speed will play the sample in reverse.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "playback:set_sample"></a>
+    <strong>playback:set_sample(smp)</strong>
+    </dt>
+    <dd>
+    Set playback sample.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">smp</span>
+            <span class="types"><a class="type" href="../classes/sample.html#">sample</a></span>
+
+
+
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "playback:stop"></a>
+    <strong>playback:stop()</strong>
+    </dt>
+    <dd>
+    Stop playback. </p>
+
+<p>Equivalent to <a href="../classes/playback.html#playback:pause">playback.pause</a>; <a href="../classes/playback.html#playback:reset">playback.reset</a>.
+
+
+
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/sample.html b/doc/classes/sample.html
new file mode 100644
index 0000000..313d14d
--- /dev/null
+++ b/doc/classes/sample.html
@@ -0,0 +1,203 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><strong>sample</strong></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>sample</code></h1>
+<p>Load audio samples.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> msample = <span class="global">require</span> <span class="string">'melisma.sample'</span>
+
+<span class="keyword">local</span> smp = msample.<span class="global">load</span>(<span class="string">'sample.wav'</span>)
+
+<span class="global">print</span>(smp:<span class="function-name">length</span>())
+<span class="global">print</span>(smp:<span class="function-name">path</span>())
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#sample.load">sample.load(path)</a></td>
+	<td class="summary">Load an audio sample.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#sample:length">sample:length()</a></td>
+	<td class="summary">Get sample length.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#sample:path">sample:path()</a></td>
+	<td class="summary">Get sample path.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "sample.load"></a>
+    <strong>sample.load(path)</strong>
+    </dt>
+    <dd>
+    Load an audio sample. </p>
+
+<p>If necessary, the audio will be resampled to the current sample rate.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">path</span>
+            <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.4">string</a></span>
+
+
+
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/sample.html#">sample</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "sample:length"></a>
+    <strong>sample:length()</strong>
+    </dt>
+    <dd>
+    Get sample length.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><span class="type">number</span></span>
+        The length of the sample in seconds.
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "sample:path"></a>
+    <strong>sample:path()</strong>
+    </dt>
+    <dd>
+    Get sample path.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.4">string</a></span>
+        The path that the sample was loaded from.
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/serial.html b/doc/classes/serial.html
new file mode 100644
index 0000000..ca72d57
--- /dev/null
+++ b/doc/classes/serial.html
@@ -0,0 +1,161 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><strong>serial</strong></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>serial</code></h1>
+<p>Read data on serial ports.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> mserial = <span class="global">require</span> <span class="string">'melisma.serial'</span>
+
+mserial.<span class="function-name">open</span> {
+    path = <span class="string">'/dev/ttyACM0'</span>,
+    callback = <span class="global">print</span>,
+}
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#serial.open">serial.open(conf)</a></td>
+	<td class="summary">Open a serial port.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "serial.open"></a>
+    <strong>serial.open(conf)</strong>
+    </dt>
+    <dd>
+
+<p>Open a serial port. </p>
+
+<p><code>conf</code> is a table containing the following keys:</p>
+
+<ul>
+    <li><code>path</code> (<strong>string, required</strong>): Path to serial port (e.g. <code>/dev/ttyACM0</code>).</li>
+    <li><code>callback</code> (<strong>function, required</strong>): Callback function for handling messages.</li>
+    <li><code>baud</code> (<strong>integer</strong>); baud rate (default <code>9600</code>).</li>
+    <li><code>format</code> (<strong>string</strong>): frame format (default <code>&apos;8N1&apos;</code>).</li>
+    <li><code>encoding</code> (<strong>string</strong>): method for encoding messages (default <code>&apos;cstring&apos;</code>). May be one of:
+    <ul>
+        <li><code>&apos;cstring&apos;</code>: <code>NULL</code>-terminated strings.</li>
+    </ul></li>
+</ul>
+
+
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">conf</span>
+            <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.6">table</a></span>
+
+
+
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/serial.html#">serial</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/classes/timer.html b/doc/classes/timer.html
new file mode 100644
index 0000000..a6b16c8
--- /dev/null
+++ b/doc/classes/timer.html
@@ -0,0 +1,226 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Methods">Methods</a></li>
+</ul>
+
+
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><strong>timer</strong></li>
+</ul>
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Class <code>timer</code></h1>
+<p>Time measurement.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> mtimer = <span class="global">require</span> <span class="string">'melisma.timer'</span>
+<span class="keyword">local</span> mkeycallback = <span class="global">require</span> <span class="string">'melisma.keycallback'</span>
+
+<span class="keyword">local</span> timer = mtimer.<span class="function-name">init</span>()
+timer:<span class="function-name">start</span>()
+
+mkeycallback.<span class="function-name">set</span>(<span class="keyword">function</span>()
+    <span class="global">print</span>(timer:<span class="function-name">read</span>())
+    timer:<span class="function-name">reset</span>()
+<span class="keyword">end</span>)
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#timer.init">timer.init()</a></td>
+	<td class="summary">Create a new timer.</td>
+	</tr>
+</table>
+<h2><a href="#Methods">Methods</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#timer:read">timer:read()</a></td>
+	<td class="summary">Read timer.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#timer:reset">timer:reset()</a></td>
+	<td class="summary">Reset timer.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#timer:start">timer:start()</a></td>
+	<td class="summary">Start timer.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#timer:stop">timer:stop()</a></td>
+	<td class="summary">Stop timer.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "timer.init"></a>
+    <strong>timer.init()</strong>
+    </dt>
+    <dd>
+    Create a new timer.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../classes/timer.html#">timer</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header "><a name="Methods"></a>Methods</h2>
+
+    <dl class="function">
+    <dt>
+    <a name = "timer:read"></a>
+    <strong>timer:read()</strong>
+    </dt>
+    <dd>
+    Read timer.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><span class="type">number</span></span>
+        Elapsed seconds.
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "timer:reset"></a>
+    <strong>timer:reset()</strong>
+    </dt>
+    <dd>
+    Reset timer.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "timer:start"></a>
+    <strong>timer:start()</strong>
+    </dt>
+    <dd>
+    Start timer.
+
+
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "timer:stop"></a>
+    <strong>timer:stop()</strong>
+    </dt>
+    <dd>
+    Stop timer.
+
+
+
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/index.html b/doc/index.html
new file mode 100644
index 0000000..f7d3c3e
--- /dev/null
+++ b/doc/index.html
@@ -0,0 +1,153 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+
+
+
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="modules/biquad.html">biquad</a></li>
+  <li><a href="modules/expression.html">expression</a></li>
+  <li><a href="modules/fs.html">fs</a></li>
+  <li><a href="modules/keycallback.html">keycallback</a></li>
+  <li><a href="modules/udp.html">udp</a></li>
+</ul>
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="classes/buffer.html">buffer</a></li>
+  <li><a href="classes/delay.html">delay</a></li>
+  <li><a href="classes/gain.html">gain</a></li>
+  <li><a href="classes/interp.html">interp</a></li>
+  <li><a href="classes/ladspa.html">ladspa</a></li>
+  <li><a href="classes/mixer.html">mixer</a></li>
+  <li><a href="classes/nullsink.html">nullsink</a></li>
+  <li><a href="classes/oscil.html">oscil</a></li>
+  <li><a href="classes/pan.html">pan</a></li>
+  <li><a href="classes/playback.html">playback</a></li>
+  <li><a href="classes/sample.html">sample</a></li>
+  <li><a href="classes/serial.html">serial</a></li>
+  <li><a href="classes/timer.html">timer</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+
+  <h2>Melisma module reference</h2>
+
+<h2>Modules</h2>
+<table class="module_list">
+	<tr>
+		<td class="name"  nowrap><a href="modules/biquad.html">biquad</a></td>
+		<td class="summary">Digital biquad filters.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="modules/expression.html">expression</a></td>
+		<td class="summary">Build filters with arithmetic expressions.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="modules/fs.html">fs</a></td>
+		<td class="summary">File system utilities.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="modules/keycallback.html">keycallback</a></td>
+		<td class="summary">Set callback for keyboard input.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="modules/udp.html">udp</a></td>
+		<td class="summary">UDP support.</td>
+	</tr>
+</table>
+<h2>Classes</h2>
+<table class="module_list">
+	<tr>
+		<td class="name"  nowrap><a href="classes/buffer.html">buffer</a></td>
+		<td class="summary">Audio buffer for capture/playback.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/delay.html">delay</a></td>
+		<td class="summary">Digital delay line.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/gain.html">gain</a></td>
+		<td class="summary">Apply gain to signals.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/interp.html">interp</a></td>
+		<td class="summary">Interpolation.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/ladspa.html">ladspa</a></td>
+		<td class="summary">LADSPA plugin support.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/mixer.html">mixer</a></td>
+		<td class="summary">Mix signals.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/nullsink.html">nullsink</a></td>
+		<td class="summary">Reference otherwise disconnected nodes.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/oscil.html">oscil</a></td>
+		<td class="summary">Wavetable backed oscillators.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/pan.html">pan</a></td>
+		<td class="summary">Panning</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/playback.html">playback</a></td>
+		<td class="summary">Audio sample playback.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/sample.html">sample</a></td>
+		<td class="summary">Load audio samples.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/serial.html">serial</a></td>
+		<td class="summary">Read data on serial ports.</td>
+	</tr>
+	<tr>
+		<td class="name"  nowrap><a href="classes/timer.html">timer</a></td>
+		<td class="summary">Time measurement.</td>
+	</tr>
+</table>
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/ldoc_fixed.css b/doc/ldoc_fixed.css
new file mode 100644
index 0000000..d7c7a6e
--- /dev/null
+++ b/doc/ldoc_fixed.css
@@ -0,0 +1,312 @@
+/* BEGIN RESET
+
+Copyright (c) 2010, Yahoo! Inc. All rights reserved.
+Code licensed under the BSD License:
+http://developer.yahoo.com/yui/license.html
+version: 2.8.2r1
+*/
+html {
+    color: #000;
+    background: #FFF;
+}
+body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,code,form,fieldset,legend,input,button,textarea,p,blockquote,th,td {
+    margin: 0;
+    padding: 0;
+}
+table {
+    border-collapse: collapse;
+    border-spacing: 0;
+}
+fieldset,img {
+    border: 0;
+}
+address,caption,cite,code,dfn,em,strong,th,var,optgroup {
+    font-style: inherit;
+    font-weight: inherit;
+}
+del,ins {
+    text-decoration: none;
+}
+li {
+    margin-left: 20px;
+}
+caption,th {
+    text-align: left;
+}
+h1,h2,h3,h4,h5,h6 {
+    font-size: 100%;
+    font-weight: bold;
+}
+q:before,q:after {
+    content: '';
+}
+abbr,acronym {
+    border: 0;
+    font-variant: normal;
+}
+sup {
+    vertical-align: baseline;
+}
+sub {
+    vertical-align: baseline;
+}
+legend {
+    color: #000;
+}
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+    background-color: rgb(245, 245, 245);
+    border: 1px solid #C0C0C0; /* silver */
+    padding: 10px;
+    margin: 10px 0 10px 0;
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+}
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+#content {
+    margin-left: 14em;
+    padding: 1em;
+    padding-left: 2em;
+    width: 700px;
+    border-left: 2px solid #cccccc;
+   // border-right: 2px solid #cccccc;
+    background-color: #ffffff;
+}
+
+#about {
+    clear: both;
+    padding-left: 1em;
+    margin-left: 14em; // avoid the damn sidebar!
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+    body {
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+        margin-left: 2%;
+        margin-right: 2%;
+        background-color: #ffffff;
+    }
+
+    #content {
+        padding: 1em;
+        background-color: #ffffff;
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+    #navigation {
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+    }
+    pre.example {
+        font-family: "Andale Mono", monospace;
+        font-size: 10pt;
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+    }
+}
+
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+    border-width: 1px;
+    border-style: solid;
+    border-color: #cccccc;
+    border-collapse: collapse;
+}
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+    border-style: solid;
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+}
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+    border-width: 1px;
+    border-style: solid;
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+}
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+    border-style: solid;
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+}
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+  background-color: #FF9;
+}
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+
diff --git a/doc/modules/biquad.html b/doc/modules/biquad.html
new file mode 100644
index 0000000..4f89b1a
--- /dev/null
+++ b/doc/modules/biquad.html
@@ -0,0 +1,189 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Class_biquad_lowpass">Class biquad.lowpass </a></li>
+</ul>
+
+
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><strong>biquad</strong></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Module <code>biquad</code></h1>
+<p>Digital biquad filters.</p>
+<p>
+
+</p>
+
+
+<h2><a href="#Class_biquad_lowpass">Class biquad.lowpass </a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#biquad.lowpass.init">biquad.lowpass.init(input)</a></td>
+	<td class="summary">Create a lowpass filter.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#lowpass:cutoff">lowpass:cutoff(cut)</a></td>
+	<td class="summary">Set filter cutoff frequency.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#lowpass:resonance">lowpass:resonance(res)</a></td>
+	<td class="summary">Set filter resonance.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header has-description"><a name="Class_biquad_lowpass"></a>Class biquad.lowpass </h2>
+
+          <div class="section-description">
+          Lowpass filter.
+          </div>
+            <h3>Usage:</h3>
+            <pre class="example"><span class="keyword">local</span> mbiquad = <span class="global">require</span> <span class="string">'melisma.biquad'</span>
+<span class="keyword">local</span> input = ...
+<span class="keyword">local</span> lowpass = mbiquad.lowpass.<span class="function-name">init</span>(node, <span class="number">2000</span>, <span class="number">0.6</span>)
+lowpass:<span class="function-name">resonance</span>(<span class="number">1000</span>)
+lowpass:<span class="function-name">cutoff</span>(<span class="number">0.25</span>)</pre>
+    <dl class="function">
+    <dt>
+    <a name = "biquad.lowpass.init"></a>
+    <strong>biquad.lowpass.init(input)</strong>
+    </dt>
+    <dd>
+    Create a lowpass filter.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">input</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signal.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../modules/biquad.html#biquad.lowpass">biquad.lowpass</a></span>
+        The newly created lowpass filter.
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "lowpass:cutoff"></a>
+    <strong>lowpass:cutoff(cut)</strong>
+    </dt>
+    <dd>
+    Set filter cutoff frequency.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">cut</span>
+            <span class="types"><span class="type">number</span></span>
+         Cutoff frequency.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "lowpass:resonance"></a>
+    <strong>lowpass:resonance(res)</strong>
+    </dt>
+    <dd>
+    Set filter resonance.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">res</span>
+            <span class="types"><span class="type">number</span></span>
+         Resonance.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/modules/expression.html b/doc/modules/expression.html
new file mode 100644
index 0000000..e0f2f6e
--- /dev/null
+++ b/doc/modules/expression.html
@@ -0,0 +1,221 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+<li><a href="#Class_script">Class script </a></li>
+</ul>
+
+
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><strong>expression</strong></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Module <code>expression</code></h1>
+<p>Build filters with arithmetic expressions.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> mexpression = <span class="global">require</span> <span class="string">'melisma.expression'</span>
+<span class="keyword">local</span> input = mepxression.input
+
+<span class="keyword">local</span> lhs = ...
+<span class="keyword">local</span> rhs = ...
+
+<span class="keyword">local</span> script = <span class="function-name">input</span>(lhs,<span class="number">0</span>) + <span class="number">0.5</span> * <span class="function-name">input</span>(rhs,<span class="number">10</span>)
+<span class="keyword">local</span> expression = script:<span class="function-name">build</span>()
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#input">input(sig, off)</a></td>
+	<td class="summary">Introduce an input signal in the expression.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#output">output(off)</a></td>
+	<td class="summary">Introduce the output signal in the expression.</td>
+	</tr>
+</table>
+<h2><a href="#Class_script">Class script </a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#script:build">script:build()</a></td>
+	<td class="summary">Compile an expression script.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "input"></a>
+    <strong>input(sig, off)</strong>
+    </dt>
+    <dd>
+    Introduce an input signal in the expression.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">sig</span>
+            <span class="types"><span class="type">channel</span></span>
+         Input signal.
+        </li>
+        <li><span class="parameter">off</span>
+            <span class="types"><span class="type">integer</span></span>
+         Offset in no. of samples.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../modules/expression.html#script">script</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "output"></a>
+    <strong>output(off)</strong>
+    </dt>
+    <dd>
+    Introduce the output signal in the expression.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">off</span>
+            <span class="types"><span class="type">integer</span></span>
+         Offset in no. of samples.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../modules/expression.html#script">script</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header has-description"><a name="Class_script"></a>Class script </h2>
+
+          <div class="section-description">
+          Represents an expression before compilation.
+Implements <code>__add</code>, <code>__sub</code>, <code>__mul</code> and <code>__div</code> for
+combining scripts in to larger ones.
+          </div>
+    <dl class="function">
+    <dt>
+    <a name = "script:build"></a>
+    <strong>script:build()</strong>
+    </dt>
+    <dd>
+    Compile an expression script.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><span class="type">expression</span></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/modules/fs.html b/doc/modules/fs.html
new file mode 100644
index 0000000..bfe5be3
--- /dev/null
+++ b/doc/modules/fs.html
@@ -0,0 +1,138 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+</ul>
+
+
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><strong>fs</strong></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Module <code>fs</code></h1>
+<p>File system utilities.</p>
+<p>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#readdir">readdir(path)</a></td>
+	<td class="summary">List directory contents.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "readdir"></a>
+    <strong>readdir(path)</strong>
+    </dt>
+    <dd>
+    List directory contents.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">path</span>
+            <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.4">string</a></span>
+         Directory path.
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.6">table</a></span>
+        Directory contents.
+    </ol>
+
+
+
+    <h3>Usage:</h3>
+    <ul>
+        <pre class="example"><span class="keyword">local</span> fs = <span class="global">require</span> <span class="string">'melisma.fs'</span>
+<span class="keyword">local</span> contents = fs.<span class="function-name">readdir</span>(<span class="string">'.'</span>)
+<span class="keyword">for</span> _,entry <span class="keyword">in</span> <span class="global">ipairs</span>(contents) <span class="keyword">do</span>
+	<span class="global">print</span>(entry.name, entry.<span class="global">type</span>)
+<span class="keyword">end</span></pre>
+    </ul>
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/modules/keycallback.html b/doc/modules/keycallback.html
new file mode 100644
index 0000000..af74b90
--- /dev/null
+++ b/doc/modules/keycallback.html
@@ -0,0 +1,133 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Functions">Functions</a></li>
+</ul>
+
+
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><strong>keycallback</strong></li>
+  <li><a href="../modules/udp.html">udp</a></li>
+</ul>
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Module <code>keycallback</code></h1>
+<p>Set callback for keyboard input.</p>
+<p>
+
+
+<pre>
+<span class="keyword">local</span> mkeycallback = <span class="global">require</span> <span class="string">'melisma.keycallback'</span>
+
+mkeycallback.<span class="function-name">set</span>(<span class="keyword">function</span>(c)
+    <span class="global">print</span>(<span class="string">'you pressed'</span>, c)
+<span class="keyword">end</span>)
+</pre>
+
+</p>
+
+
+<h2><a href="#Functions">Functions</a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#set">set(fn)</a></td>
+	<td class="summary">Set the callback.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header "><a name="Functions"></a>Functions</h2>
+    Methods
+    <dl class="function">
+    <dt>
+    <a name = "set"></a>
+    <strong>set(fn)</strong>
+    </dt>
+    <dd>
+    Set the callback.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">fn</span>
+            <span class="types"><span class="type">function</span></span>
+         Callback function.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/doc/modules/udp.html b/doc/modules/udp.html
new file mode 100644
index 0000000..f19c300
--- /dev/null
+++ b/doc/modules/udp.html
@@ -0,0 +1,311 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+<head>
+    <title>Melisma modules</title>
+    <link rel="stylesheet" href="../ldoc_fixed.css" type="text/css" />
+</head>
+<body>
+
+<div id="container">
+
+<div id="product">
+	<div id="product_logo"></div>
+	<div id="product_name"><big><b></b></big></div>
+	<div id="product_description"></div>
+</div> <!-- id="product" -->
+
+
+<div id="main">
+
+
+<!-- Menu -->
+
+<div id="navigation">
+<p><a href="/melisma-modules">Back to repository</a></p>
+<br/>
+<h1>Melisma modules</h1>
+
+
+<ul>
+  <li><a href="../index.html">Index</a></li>
+</ul>
+
+<h2>Contents</h2>
+<ul>
+<li><a href="#Class_sockaddr">Class sockaddr </a></li>
+<li><a href="#Class_socket">Class socket </a></li>
+</ul>
+
+
+<h2>Modules</h2>
+<ul class="nowrap">
+  <li><a href="../modules/biquad.html">biquad</a></li>
+  <li><a href="../modules/expression.html">expression</a></li>
+  <li><a href="../modules/fs.html">fs</a></li>
+  <li><a href="../modules/keycallback.html">keycallback</a></li>
+  <li><strong>udp</strong></li>
+</ul>
+<h2>Classes</h2>
+<ul class="nowrap">
+  <li><a href="../classes/buffer.html">buffer</a></li>
+  <li><a href="../classes/delay.html">delay</a></li>
+  <li><a href="../classes/gain.html">gain</a></li>
+  <li><a href="../classes/interp.html">interp</a></li>
+  <li><a href="../classes/ladspa.html">ladspa</a></li>
+  <li><a href="../classes/mixer.html">mixer</a></li>
+  <li><a href="../classes/nullsink.html">nullsink</a></li>
+  <li><a href="../classes/oscil.html">oscil</a></li>
+  <li><a href="../classes/pan.html">pan</a></li>
+  <li><a href="../classes/playback.html">playback</a></li>
+  <li><a href="../classes/sample.html">sample</a></li>
+  <li><a href="../classes/serial.html">serial</a></li>
+  <li><a href="../classes/timer.html">timer</a></li>
+</ul>
+
+</div>
+
+<div id="content">
+
+<h1>Module <code>udp</code></h1>
+<p>UDP support.</p>
+<p>
+
+
+
+<pre>
+<span class="keyword">local</span> mudp = <span class="global">require</span> <span class="string">'melisma.udp'</span>
+
+<span class="keyword">local</span> addr = mudp.sockaddr.<span class="function-name">inet</span>(<span class="string">'127.0.0.1'</span>,<span class="number">8000</span>)
+<span class="keyword">local</span> sock = mudp.socket.<span class="function-name">inet</span>()
+
+sock:<span class="function-name">send</span>(addr,<span class="string">'hello'</span>)
+sock:<span class="function-name">bind</span>(addr,<span class="global">print</span>)
+</pre>
+
+</p>
+
+
+<h2><a href="#Class_sockaddr">Class sockaddr </a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#sockaddr.inet">sockaddr.inet(host, port)</a></td>
+	<td class="summary">Create a internet domain address description.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#sockaddr.unix">sockaddr.unix(path)</a></td>
+	<td class="summary">Create a unix domain address description.</td>
+	</tr>
+</table>
+<h2><a href="#Class_socket">Class socket </a></h2>
+<table class="function_list">
+	<tr>
+	<td class="name" nowrap><a href="#socket.inet">socket.inet()</a></td>
+	<td class="summary">Create an internet domain socket.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#socket.unix">socket.unix()</a></td>
+	<td class="summary">Create a unix domain socket.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#socket:bind">socket:bind(addr, fn)</a></td>
+	<td class="summary">Bind a socket to an address.</td>
+	</tr>
+	<tr>
+	<td class="name" nowrap><a href="#socket:send">socket:send(addr, pkt)</a></td>
+	<td class="summary">Send a packet on a socket.</td>
+	</tr>
+</table>
+
+<br/>
+<br/>
+
+
+    <h2 class="section-header has-description"><a name="Class_sockaddr"></a>Class sockaddr </h2>
+
+          <div class="section-description">
+          Socket address description.
+          </div>
+    <dl class="function">
+    <dt>
+    <a name = "sockaddr.inet"></a>
+    <strong>sockaddr.inet(host, port)</strong>
+    </dt>
+    <dd>
+    Create a internet domain address description.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">host</span>
+            <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.4">string</a></span>
+
+
+
+        </li>
+        <li><span class="parameter">port</span>
+            <span class="types"><span class="type">integer</span></span>
+
+
+
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../modules/udp.html#sockaddr">sockaddr</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "sockaddr.unix"></a>
+    <strong>sockaddr.unix(path)</strong>
+    </dt>
+    <dd>
+    Create a unix domain address description.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">path</span>
+            <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.4">string</a></span>
+
+
+
+        </li>
+    </ul>
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../modules/udp.html#sockaddr">sockaddr</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+</dl>
+    <h2 class="section-header has-description"><a name="Class_socket"></a>Class socket </h2>
+
+          <div class="section-description">
+          Handle to a socket.
+          </div>
+    <dl class="function">
+    <dt>
+    <a name = "socket.inet"></a>
+    <strong>socket.inet()</strong>
+    </dt>
+    <dd>
+    Create an internet domain socket.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../modules/udp.html#socket">socket</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "socket.unix"></a>
+    <strong>socket.unix()</strong>
+    </dt>
+    <dd>
+    Create a unix domain socket.
+
+
+
+    <h3>Returns:</h3>
+    <ol>
+
+           <span class="types"><a class="type" href="../modules/udp.html#socket">socket</a></span>
+
+
+
+    </ol>
+
+
+
+
+</dd>
+    <dt>
+    <a name = "socket:bind"></a>
+    <strong>socket:bind(addr, fn)</strong>
+    </dt>
+    <dd>
+    Bind a socket to an address.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">addr</span>
+            <span class="types"><a class="type" href="../modules/udp.html#sockaddr">sockaddr</a></span>
+         Address description.
+        </li>
+        <li><span class="parameter">fn</span>
+            <span class="types"><span class="type">function</span></span>
+         Packet callback function.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+    <dt>
+    <a name = "socket:send"></a>
+    <strong>socket:send(addr, pkt)</strong>
+    </dt>
+    <dd>
+    Send a packet on a socket.
+
+
+    <h3>Parameters:</h3>
+    <ul>
+        <li><span class="parameter">addr</span>
+            <span class="types"><a class="type" href="../modules/udp.html#sockaddr">sockaddr</a></span>
+         Address description.
+        </li>
+        <li><span class="parameter">pkt</span>
+            <span class="types"><a class="type" href="https://www.lua.org/manual/5.3/manual.html#6.4">string</a></span>
+         Packet to send.
+        </li>
+    </ul>
+
+
+
+
+
+</dd>
+</dl>
+
+
+</div> <!-- id="content" -->
+</div> <!-- id="main" -->
+<div id="about">
+<i>generated by <a href="http://github.com/lunarmodules/LDoc">LDoc 1.5.0</a></i>
+<i style="float:right;">Last updated 1980-01-01 00:00:00 </i>
+</div> <!-- id="about" -->
+</div> <!-- id="container" -->
+</body>
+</html>
diff --git a/external/ladspa.h b/external/ladspa.h
new file mode 100644
index 0000000..b1a9c4e
--- /dev/null
+++ b/external/ladspa.h
@@ -0,0 +1,603 @@
+/* ladspa.h
+
+   Linux Audio Developer's Simple Plugin API Version 1.1[LGPL].
+   Copyright (C) 2000-2002 Richard W.E. Furse, Paul Barton-Davis,
+   Stefan Westerfeld.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License
+   as published by the Free Software Foundation; either version 2.1 of
+   the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+   USA. */
+
+#ifndef LADSPA_INCLUDED
+#define LADSPA_INCLUDED
+
+#define LADSPA_VERSION "1.1"
+#define LADSPA_VERSION_MAJOR 1
+#define LADSPA_VERSION_MINOR 1
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*****************************************************************************/
+
+/* Overview:
+
+   There is a large number of synthesis packages in use or development
+   on the Linux platform at this time. This API (`The Linux Audio
+   Developer's Simple Plugin API') attempts to give programmers the
+   ability to write simple `plugin' audio processors in C/C++ and link
+   them dynamically (`plug') into a range of these packages (`hosts').
+   It should be possible for any host and any plugin to communicate
+   completely through this interface.
+
+   This API is deliberately short and simple. To achieve compatibility
+   with a range of promising Linux sound synthesis packages it
+   attempts to find the `greatest common divisor' in their logical
+   behaviour. Having said this, certain limiting decisions are
+   implicit, notably the use of a fixed type (LADSPA_Data) for all
+   data transfer and absence of a parameterised `initialisation'
+   phase. See below for the LADSPA_Data typedef.
+
+   Plugins are expected to distinguish between control and audio
+   data. Plugins have `ports' that are inputs or outputs for audio or
+   control data and each plugin is `run' for a `block' corresponding
+   to a short time interval measured in samples. Audio data is
+   communicated using arrays of LADSPA_Data, allowing a block of audio
+   to be processed by the plugin in a single pass. Control data is
+   communicated using single LADSPA_Data values. Control data has a
+   single value at the start of a call to the `run()' or `run_adding()'
+   function, and may be considered to remain this value for its
+   duration. The plugin may assume that all its input and output ports
+   have been connected to the relevant data location (see the
+   `connect_port()' function below) before it is asked to run.
+
+   Plugins will reside in shared object files suitable for dynamic
+   linking by dlopen() and family. The file will provide a number of
+   `plugin types' that can be used to instantiate actual plugins
+   (sometimes known as `plugin instances') that can be connected
+   together to perform tasks.
+
+   This API contains very limited error-handling. */
+
+/*****************************************************************************/
+
+/* Fundamental data type passed in and out of plugin. This data type
+   is used to communicate audio samples and control values. It is
+   assumed that the plugin will work sensibly given any numeric input
+   value although it may have a preferred range (see hints below).
+
+   For audio it is generally assumed that 1.0f is the `0dB' reference
+   amplitude and is a `normal' signal level. */
+
+typedef float LADSPA_Data;
+
+/*****************************************************************************/
+
+/* Special Plugin Properties:
+
+   Optional features of the plugin type are encapsulated in the
+   LADSPA_Properties type. This is assembled by ORing individual
+   properties together. */
+
+typedef int LADSPA_Properties;
+
+/* Property LADSPA_PROPERTY_REALTIME indicates that the plugin has a
+   real-time dependency (e.g. listens to a MIDI device) and so its
+   output must not be cached or subject to significant latency. */
+#define LADSPA_PROPERTY_REALTIME        0x1
+
+/* Property LADSPA_PROPERTY_INPLACE_BROKEN indicates that the plugin
+   may cease to work correctly if the host elects to use the same data
+   location for both input and output (see connect_port()). This
+   should be avoided as enabling this flag makes it impossible for
+   hosts to use the plugin to process audio `in-place.' */
+#define LADSPA_PROPERTY_INPLACE_BROKEN  0x2
+
+/* Property LADSPA_PROPERTY_HARD_RT_CAPABLE indicates that the plugin
+   is capable of running not only in a conventional host but also in a
+   `hard real-time' environment. To qualify for this the plugin must
+   satisfy all of the following:
+
+   (1) The plugin must not use malloc(), free() or other heap memory
+   management within its run() or run_adding() functions. All new
+   memory used in run() must be managed via the stack. These
+   restrictions only apply to the run() function.
+
+   (2) The plugin will not attempt to make use of any library
+   functions with the exceptions of functions in the ANSI standard C
+   and C maths libraries, which the host is expected to provide.
+
+   (3) The plugin will not access files, devices, pipes, sockets, IPC
+   or any other mechanism that might result in process or thread
+   blocking.
+
+   (4) The plugin will take an amount of time to execute a run() or
+   run_adding() call approximately of form (A+B*SampleCount) where A
+   and B depend on the machine and host in use. This amount of time
+   may not depend on input signals or plugin state. The host is left
+   the responsibility to perform timings to estimate upper bounds for
+   A and B. */
+#define LADSPA_PROPERTY_HARD_RT_CAPABLE 0x4
+
+#define LADSPA_IS_REALTIME(x)        ((x) & LADSPA_PROPERTY_REALTIME)
+#define LADSPA_IS_INPLACE_BROKEN(x)  ((x) & LADSPA_PROPERTY_INPLACE_BROKEN)
+#define LADSPA_IS_HARD_RT_CAPABLE(x) ((x) & LADSPA_PROPERTY_HARD_RT_CAPABLE)
+
+/*****************************************************************************/
+
+/* Plugin Ports:
+
+   Plugins have `ports' that are inputs or outputs for audio or
+   data. Ports can communicate arrays of LADSPA_Data (for audio
+   inputs/outputs) or single LADSPA_Data values (for control
+   input/outputs). This information is encapsulated in the
+   LADSPA_PortDescriptor type which is assembled by ORing individual
+   properties together.
+
+   Note that a port must be an input or an output port but not both
+   and that a port must be a control or audio port but not both. */
+
+typedef int LADSPA_PortDescriptor;
+
+/* Property LADSPA_PORT_INPUT indicates that the port is an input. */
+#define LADSPA_PORT_INPUT   0x1
+
+/* Property LADSPA_PORT_OUTPUT indicates that the port is an output. */
+#define LADSPA_PORT_OUTPUT  0x2
+
+/* Property LADSPA_PORT_CONTROL indicates that the port is a control
+   port. */
+#define LADSPA_PORT_CONTROL 0x4
+
+/* Property LADSPA_PORT_AUDIO indicates that the port is a audio
+   port. */
+#define LADSPA_PORT_AUDIO   0x8
+
+#define LADSPA_IS_PORT_INPUT(x)   ((x) & LADSPA_PORT_INPUT)
+#define LADSPA_IS_PORT_OUTPUT(x)  ((x) & LADSPA_PORT_OUTPUT)
+#define LADSPA_IS_PORT_CONTROL(x) ((x) & LADSPA_PORT_CONTROL)
+#define LADSPA_IS_PORT_AUDIO(x)   ((x) & LADSPA_PORT_AUDIO)
+
+/*****************************************************************************/
+
+/* Plugin Port Range Hints:
+
+   The host may wish to provide a representation of data entering or
+   leaving a plugin (e.g. to generate a GUI automatically). To make
+   this more meaningful, the plugin should provide `hints' to the host
+   describing the usual values taken by the data.
+
+   Note that these are only hints. The host may ignore them and the
+   plugin must not assume that data supplied to it is meaningful. If
+   the plugin receives invalid input data it is expected to continue
+   to run without failure and, where possible, produce a sensible
+   output (e.g. a high-pass filter given a negative cutoff frequency
+   might switch to an all-pass mode).
+
+   Hints are meaningful for all input and output ports but hints for
+   input control ports are expected to be particularly useful.
+
+   More hint information is encapsulated in the
+   LADSPA_PortRangeHintDescriptor type which is assembled by ORing
+   individual hint types together. Hints may require further
+   LowerBound and UpperBound information.
+
+   All the hint information for a particular port is aggregated in the
+   LADSPA_PortRangeHint structure. */
+
+typedef int LADSPA_PortRangeHintDescriptor;
+
+/* Hint LADSPA_HINT_BOUNDED_BELOW indicates that the LowerBound field
+   of the LADSPA_PortRangeHint should be considered meaningful. The
+   value in this field should be considered the (inclusive) lower
+   bound of the valid range. If LADSPA_HINT_SAMPLE_RATE is also
+   specified then the value of LowerBound should be multiplied by the
+   sample rate. */
+#define LADSPA_HINT_BOUNDED_BELOW   0x1
+
+/* Hint LADSPA_HINT_BOUNDED_ABOVE indicates that the UpperBound field
+   of the LADSPA_PortRangeHint should be considered meaningful. The
+   value in this field should be considered the (inclusive) upper
+   bound of the valid range. If LADSPA_HINT_SAMPLE_RATE is also
+   specified then the value of UpperBound should be multiplied by the
+   sample rate. */
+#define LADSPA_HINT_BOUNDED_ABOVE   0x2
+
+/* Hint LADSPA_HINT_TOGGLED indicates that the data item should be
+   considered a Boolean toggle. Data less than or equal to zero should
+   be considered `off' or `false,' and data above zero should be
+   considered `on' or `true.' LADSPA_HINT_TOGGLED may not be used in
+   conjunction with any other hint except LADSPA_HINT_DEFAULT_0 or
+   LADSPA_HINT_DEFAULT_1. */
+#define LADSPA_HINT_TOGGLED         0x4
+
+/* Hint LADSPA_HINT_SAMPLE_RATE indicates that any bounds specified
+   should be interpreted as multiples of the sample rate. For
+   instance, a frequency range from 0Hz to the Nyquist frequency (half
+   the sample rate) could be requested by this hint in conjunction
+   with LowerBound = 0 and UpperBound = 0.5. Hosts that support bounds
+   at all must support this hint to retain meaning. */
+#define LADSPA_HINT_SAMPLE_RATE     0x8
+
+/* Hint LADSPA_HINT_LOGARITHMIC indicates that it is likely that the
+   user will find it more intuitive to view values using a logarithmic
+   scale. This is particularly useful for frequencies and gains. */
+#define LADSPA_HINT_LOGARITHMIC     0x10
+
+/* Hint LADSPA_HINT_INTEGER indicates that a user interface would
+   probably wish to provide a stepped control taking only integer
+   values. Any bounds set should be slightly wider than the actual
+   integer range required to avoid floating point rounding errors. For
+   instance, the integer set {0,1,2,3} might be described as [-0.1,
+   3.1]. */
+#define LADSPA_HINT_INTEGER         0x20
+
+/* The various LADSPA_HINT_HAS_DEFAULT_* hints indicate a `normal'
+   value for the port that is sensible as a default. For instance,
+   this value is suitable for use as an initial value in a user
+   interface or as a value the host might assign to a control port
+   when the user has not provided one. Defaults are encoded using a
+   mask so only one default may be specified for a port. Some of the
+   hints make use of lower and upper bounds, in which case the
+   relevant bound or bounds must be available and
+   LADSPA_HINT_SAMPLE_RATE must be applied as usual. The resulting
+   default must be rounded if LADSPA_HINT_INTEGER is present. Default
+   values were introduced in LADSPA v1.1. */
+#define LADSPA_HINT_DEFAULT_MASK    0x3C0
+
+/* This default values indicates that no default is provided. */
+#define LADSPA_HINT_DEFAULT_NONE    0x0
+
+/* This default hint indicates that the suggested lower bound for the
+   port should be used. */
+#define LADSPA_HINT_DEFAULT_MINIMUM 0x40
+
+/* This default hint indicates that a low value between the suggested
+   lower and upper bounds should be chosen. For ports with
+   LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.75 +
+   log(upper) * 0.25). Otherwise, this should be (lower * 0.75 + upper
+   * 0.25). */
+#define LADSPA_HINT_DEFAULT_LOW     0x80
+
+/* This default hint indicates that a middle value between the
+   suggested lower and upper bounds should be chosen. For ports with
+   LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.5 +
+   log(upper) * 0.5). Otherwise, this should be (lower * 0.5 + upper *
+   0.5). */
+#define LADSPA_HINT_DEFAULT_MIDDLE  0xC0
+
+/* This default hint indicates that a high value between the suggested
+   lower and upper bounds should be chosen. For ports with
+   LADSPA_HINT_LOGARITHMIC, this should be exp(log(lower) * 0.25 +
+   log(upper) * 0.75). Otherwise, this should be (lower * 0.25 + upper
+   * 0.75). */
+#define LADSPA_HINT_DEFAULT_HIGH    0x100
+
+/* This default hint indicates that the suggested upper bound for the
+   port should be used. */
+#define LADSPA_HINT_DEFAULT_MAXIMUM 0x140
+
+/* This default hint indicates that the number 0 should be used. Note
+   that this default may be used in conjunction with
+   LADSPA_HINT_TOGGLED. */
+#define LADSPA_HINT_DEFAULT_0       0x200
+
+/* This default hint indicates that the number 1 should be used. Note
+   that this default may be used in conjunction with
+   LADSPA_HINT_TOGGLED. */
+#define LADSPA_HINT_DEFAULT_1       0x240
+
+/* This default hint indicates that the number 100 should be used. */
+#define LADSPA_HINT_DEFAULT_100     0x280
+
+/* This default hint indicates that the Hz frequency of `concert A'
+   should be used. This will be 440 unless the host uses an unusual
+   tuning convention, in which case it may be within a few Hz. */
+#define LADSPA_HINT_DEFAULT_440     0x2C0
+
+#define LADSPA_IS_HINT_BOUNDED_BELOW(x)   ((x) & LADSPA_HINT_BOUNDED_BELOW)
+#define LADSPA_IS_HINT_BOUNDED_ABOVE(x)   ((x) & LADSPA_HINT_BOUNDED_ABOVE)
+#define LADSPA_IS_HINT_TOGGLED(x)         ((x) & LADSPA_HINT_TOGGLED)
+#define LADSPA_IS_HINT_SAMPLE_RATE(x)     ((x) & LADSPA_HINT_SAMPLE_RATE)
+#define LADSPA_IS_HINT_LOGARITHMIC(x)     ((x) & LADSPA_HINT_LOGARITHMIC)
+#define LADSPA_IS_HINT_INTEGER(x)         ((x) & LADSPA_HINT_INTEGER)
+
+#define LADSPA_IS_HINT_HAS_DEFAULT(x)     ((x) & LADSPA_HINT_DEFAULT_MASK)
+#define LADSPA_IS_HINT_DEFAULT_MINIMUM(x) (((x) & LADSPA_HINT_DEFAULT_MASK)   \
+                                           == LADSPA_HINT_DEFAULT_MINIMUM)
+#define LADSPA_IS_HINT_DEFAULT_LOW(x)     (((x) & LADSPA_HINT_DEFAULT_MASK)   \
+                                           == LADSPA_HINT_DEFAULT_LOW)
+#define LADSPA_IS_HINT_DEFAULT_MIDDLE(x)  (((x) & LADSPA_HINT_DEFAULT_MASK)   \
+                                           == LADSPA_HINT_DEFAULT_MIDDLE)
+#define LADSPA_IS_HINT_DEFAULT_HIGH(x)    (((x) & LADSPA_HINT_DEFAULT_MASK)   \
+                                           == LADSPA_HINT_DEFAULT_HIGH)
+#define LADSPA_IS_HINT_DEFAULT_MAXIMUM(x) (((x) & LADSPA_HINT_DEFAULT_MASK)   \
+                                           == LADSPA_HINT_DEFAULT_MAXIMUM)
+#define LADSPA_IS_HINT_DEFAULT_0(x)       (((x) & LADSPA_HINT_DEFAULT_MASK)   \
+                                           == LADSPA_HINT_DEFAULT_0)
+#define LADSPA_IS_HINT_DEFAULT_1(x)       (((x) & LADSPA_HINT_DEFAULT_MASK)   \
+                                           == LADSPA_HINT_DEFAULT_1)
+#define LADSPA_IS_HINT_DEFAULT_100(x)     (((x) & LADSPA_HINT_DEFAULT_MASK)   \
+                                           == LADSPA_HINT_DEFAULT_100)
+#define LADSPA_IS_HINT_DEFAULT_440(x)     (((x) & LADSPA_HINT_DEFAULT_MASK)   \
+                                            == LADSPA_HINT_DEFAULT_440)
+
+typedef struct _LADSPA_PortRangeHint {
+
+  /* Hints about the port. */
+  LADSPA_PortRangeHintDescriptor HintDescriptor;
+
+  /* Meaningful when hint LADSPA_HINT_BOUNDED_BELOW is active. When
+     LADSPA_HINT_SAMPLE_RATE is also active then this value should be
+     multiplied by the relevant sample rate. */
+  LADSPA_Data LowerBound;
+
+  /* Meaningful when hint LADSPA_HINT_BOUNDED_ABOVE is active. When
+     LADSPA_HINT_SAMPLE_RATE is also active then this value should be
+     multiplied by the relevant sample rate. */
+  LADSPA_Data UpperBound;
+
+} LADSPA_PortRangeHint;
+
+/*****************************************************************************/
+
+/* Plugin Handles:
+
+   This plugin handle indicates a particular instance of the plugin
+   concerned. It is valid to compare this to NULL (0 for C++) but
+   otherwise the host should not attempt to interpret it. The plugin
+   may use it to reference internal instance data. */
+
+typedef void * LADSPA_Handle;
+
+/*****************************************************************************/
+
+/* Descriptor for a Type of Plugin:
+
+   This structure is used to describe a plugin type. It provides a
+   number of functions to examine the type, instantiate it, link it to
+   buffers and workspaces and to run it. */
+
+typedef struct _LADSPA_Descriptor {
+
+  /* This numeric identifier indicates the plugin type
+     uniquely. Plugin programmers may reserve ranges of IDs from a
+     central body to avoid clashes. Hosts may assume that IDs are
+     below 0x1000000. */
+  unsigned long UniqueID;
+
+  /* This identifier can be used as a unique, case-sensitive
+     identifier for the plugin type within the plugin file. Plugin
+     types should be identified by file and label rather than by index
+     or plugin name, which may be changed in new plugin
+     versions. Labels must not contain white-space characters. */
+  const char * Label;
+
+  /* This indicates a number of properties of the plugin. */
+  LADSPA_Properties Properties;
+
+  /* This member points to the null-terminated name of the plugin
+     (e.g. "Sine Oscillator"). */
+  const char * Name;
+
+  /* This member points to the null-terminated string indicating the
+     maker of the plugin. This can be an empty string but not NULL. */
+  const char * Maker;
+
+  /* This member points to the null-terminated string indicating any
+     copyright applying to the plugin. If no Copyright applies the
+     string "None" should be used. */
+  const char * Copyright;
+
+  /* This indicates the number of ports (input AND output) present on
+     the plugin. */
+  unsigned long PortCount;
+
+  /* This member indicates an array of port descriptors. Valid indices
+     vary from 0 to PortCount-1. */
+  const LADSPA_PortDescriptor * PortDescriptors;
+
+  /* This member indicates an array of null-terminated strings
+     describing ports (e.g. "Frequency (Hz)"). Valid indices vary from
+     0 to PortCount-1. */
+  const char * const * PortNames;
+
+  /* This member indicates an array of range hints for each port (see
+     above). Valid indices vary from 0 to PortCount-1. */
+  const LADSPA_PortRangeHint * PortRangeHints;
+
+  /* This may be used by the plugin developer to pass any custom
+     implementation data into an instantiate call. It must not be used
+     or interpreted by the host. It is expected that most plugin
+     writers will not use this facility as LADSPA_Handle should be
+     used to hold instance data. */
+  void * ImplementationData;
+
+  /* This member is a function pointer that instantiates a plugin. A
+     handle is returned indicating the new plugin instance. The
+     instantiation function accepts a sample rate as a parameter. The
+     plugin descriptor from which this instantiate function was found
+     must also be passed. This function must return NULL if
+     instantiation fails.
+
+     Note that instance initialisation should generally occur in
+     activate() rather than here. */
+  LADSPA_Handle (*instantiate)(const struct _LADSPA_Descriptor * Descriptor,
+                               unsigned long                     SampleRate);
+
+  /* This member is a function pointer that connects a port on an
+     instantiated plugin to a memory location at which a block of data
+     for the port will be read/written. The data location is expected
+     to be an array of LADSPA_Data for audio ports or a single
+     LADSPA_Data value for control ports. Memory issues will be
+     managed by the host. The plugin must read/write the data at these
+     locations every time run() or run_adding() is called and the data
+     present at the time of this connection call should not be
+     considered meaningful.
+
+     connect_port() may be called more than once for a plugin instance
+     to allow the host to change the buffers that the plugin is
+     reading or writing. These calls may be made before or after
+     activate() or deactivate() calls.
+
+     connect_port() must be called at least once for each port before
+     run() or run_adding() is called. When working with blocks of
+     LADSPA_Data the plugin should pay careful attention to the block
+     size passed to the run function as the block allocated may only
+     just be large enough to contain the block of samples.
+
+     Plugin writers should be aware that the host may elect to use the
+     same buffer for more than one port and even use the same buffer
+     for both input and output (see LADSPA_PROPERTY_INPLACE_BROKEN).
+     However, overlapped buffers or use of a single buffer for both
+     audio and control data may result in unexpected behaviour. */
+   void (*connect_port)(LADSPA_Handle Instance,
+                        unsigned long Port,
+                        LADSPA_Data * DataLocation);
+
+  /* This member is a function pointer that initialises a plugin
+     instance and activates it for use. This is separated from
+     instantiate() to aid real-time support and so that hosts can
+     reinitialise a plugin instance by calling deactivate() and then
+     activate(). In this case the plugin instance must reset all state
+     information dependent on the history of the plugin instance
+     except for any data locations provided by connect_port() and any
+     gain set by set_run_adding_gain(). If there is nothing for
+     activate() to do then the plugin writer may provide a NULL rather
+     than an empty function.
+
+     When present, hosts must call this function once before run() (or
+     run_adding()) is called for the first time. This call should be
+     made as close to the run() call as possible and indicates to
+     real-time plugins that they are now live. Plugins should not rely
+     on a prompt call to run() after activate(). activate() may not be
+     called again unless deactivate() is called first. Note that
+     connect_port() may be called before or after a call to
+     activate(). */
+  void (*activate)(LADSPA_Handle Instance);
+
+  /* This method is a function pointer that runs an instance of a
+     plugin for a block. Two parameters are required: the first is a
+     handle to the particular instance to be run and the second
+     indicates the block size (in samples) for which the plugin
+     instance may run.
+
+     Note that if an activate() function exists then it must be called
+     before run() or run_adding(). If deactivate() is called for a
+     plugin instance then the plugin instance may not be reused until
+     activate() has been called again.
+
+     If the plugin has the property LADSPA_PROPERTY_HARD_RT_CAPABLE
+     then there are various things that the plugin should not do
+     within the run() or run_adding() functions (see above). */
+  void (*run)(LADSPA_Handle Instance,
+              unsigned long SampleCount);
+
+  /* This method is a function pointer that runs an instance of a
+     plugin for a block. This has identical behaviour to run() except
+     in the way data is output from the plugin. When run() is used,
+     values are written directly to the memory areas associated with
+     the output ports. However when run_adding() is called, values
+     must be added to the values already present in the memory
+     areas. Furthermore, output values written must be scaled by the
+     current gain set by set_run_adding_gain() (see below) before
+     addition.
+
+     run_adding() is optional. When it is not provided by a plugin,
+     this function pointer must be set to NULL. When it is provided,
+     the function set_run_adding_gain() must be provided also. */
+  void (*run_adding)(LADSPA_Handle Instance,
+                     unsigned long SampleCount);
+
+  /* This method is a function pointer that sets the output gain for
+     use when run_adding() is called (see above). If this function is
+     never called the gain is assumed to default to 1. Gain
+     information should be retained when activate() or deactivate()
+     are called.
+
+     This function should be provided by the plugin if and only if the
+     run_adding() function is provided. When it is absent this
+     function pointer must be set to NULL. */
+  void (*set_run_adding_gain)(LADSPA_Handle Instance,
+                              LADSPA_Data   Gain);
+
+  /* This is the counterpart to activate() (see above). If there is
+     nothing for deactivate() to do then the plugin writer may provide
+     a NULL rather than an empty function.
+
+     Hosts must deactivate all activated units after they have been
+     run() (or run_adding()) for the last time. This call should be
+     made as close to the last run() call as possible and indicates to
+     real-time plugins that they are no longer live. Plugins should
+     not rely on prompt deactivation. Note that connect_port() may be
+     called before or after a call to deactivate().
+
+     Deactivation is not similar to pausing as the plugin instance
+     will be reinitialised when activate() is called to reuse it. */
+  void (*deactivate)(LADSPA_Handle Instance);
+
+  /* Once an instance of a plugin has been finished with it can be
+     deleted using the following function. The instance handle passed
+     ceases to be valid after this call.
+
+     If activate() was called for a plugin instance then a
+     corresponding call to deactivate() must be made before cleanup()
+     is called. */
+  void (*cleanup)(LADSPA_Handle Instance);
+
+} LADSPA_Descriptor;
+
+/**********************************************************************/
+
+/* Accessing a Plugin: */
+
+/* The exact mechanism by which plugins are loaded is host-dependent,
+   however all most hosts will need to know is the name of shared
+   object file containing the plugin types. To allow multiple hosts to
+   share plugin types, hosts may wish to check for environment
+   variable LADSPA_PATH. If present, this should contain a
+   colon-separated path indicating directories that should be searched
+   (in order) when loading plugin types.
+
+   A plugin programmer must include a function called
+   "ladspa_descriptor" with the following function prototype within
+   the shared object file. This function will have C-style linkage (if
+   you are using C++ this is taken care of by the `extern "C"' clause
+   at the top of the file).
+
+   A host will find the plugin shared object file by one means or
+   another, find the ladspa_descriptor() function, call it, and
+   proceed from there.
+
+   Plugin types are accessed by index (not ID) using values from 0
+   upwards. Out of range indexes must result in this function
+   returning NULL, so the plugin count can be determined by checking
+   for the least index that results in NULL being returned. */
+
+const LADSPA_Descriptor * ladspa_descriptor(unsigned long Index);
+
+/* Datatype corresponding to the ladspa_descriptor() function. */
+typedef const LADSPA_Descriptor *
+(*LADSPA_Descriptor_Function)(unsigned long Index);
+
+/**********************************************************************/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LADSPA_INCLUDED */
+
+/* EOF */
diff --git a/lib/distrib.lua b/lib/distrib.lua
new file mode 100644
index 0000000..e49ff88
--- /dev/null
+++ b/lib/distrib.lua
@@ -0,0 +1,38 @@
+--
+-- melisma - extensible and scriptable audio engine
+-- Copyright (C) 2026  Ludvig Gunne Lindström
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+--
+
+local M = {}
+
+function M.uniform(lo,hi)
+  return lo + math.random()*(hi - lo)
+end
+
+function M.normal(mean,dev)
+  local u,v,s,t,z0,z1
+  repeat
+    u = M.uniform(-1,1)
+    v = M.uniform(-1,1)
+    s = u^2 + v^2
+  until s > 0 and s < 1
+  t = math.sqrt(-2*math.log(s) / s)
+  z0 = mean + u*t*dev
+  z1 = mean + v*t*dev
+  return z0,z1
+end
+
+return M
diff --git a/lib/functional.lua b/lib/functional.lua
new file mode 100644
index 0000000..9f50b7e
--- /dev/null
+++ b/lib/functional.lua
@@ -0,0 +1,171 @@
+--
+-- melisma - extensible and scriptable audio engine
+-- Copyright (C) 2026  Ludvig Gunne Lindström
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+--
+
+local m_util = require 'melisma.util'
+
+local M = {}
+
+function M.fmap(f,l)
+  local res = {}
+  for k,v in pairs(l) do res[k] = f(v) end
+  return res
+end
+
+function M.compose(f,g,...)
+  local tail = table.pack(...)
+  if g == nil then return f end
+  return function(x) return f(M.compose(g,table.unpack(tail))(x)) end
+end
+
+function M.pipeline(...)
+  local args = table.pack(...)
+  return function(x)
+    for _,f in ipairs(args) do x = f(x) end
+    return x
+  end
+end
+
+function M.bind(f,...)
+  local bound = table.pack(...)
+  return function(...)
+    local free = table.pack(...)
+    local all = M.concat(bound,free)
+    return f(table.unpack(all))
+  end
+end
+
+function M.bind1(f,...)
+  local bound = table.pack(...)
+  return function(x)
+    return f(x,table.unpack(bound))
+  end
+end
+
+function M.constval(v) return function(...) return v end end
+
+function M.constfunc(f) return function(...) f() end end
+
+function M.call(f,...) return f(...) end
+
+function M.replicate(f,n)
+  local res = {}
+  for i=1,n do
+    if type(f) == 'function' then
+      table.insert(res,f())
+    else
+      table.insert(res,f)
+    end
+  end
+  return res
+end
+
+function M.id(...) return ... end
+
+function M.access(...)
+  local args = table.pack(...)
+  local x = args[#args]
+  args[#args] = nil
+
+  for _,key in ipairs(args) do
+    x = x[key]
+  end
+
+  return x
+end
+
+function M.filter(pred,list)
+  local result = {}
+
+  for _,elem in ipairs(list) do
+    if pred(elem) then
+      table.insert(result,elem)
+    end
+  end
+
+  return result
+end
+
+function M.void(...) end
+
+function M.zip(f,lhs,rhs)
+  local result = {}
+  local n = math.min(#lhs,#rhs)
+
+  for i = 1,n do
+    local v = f(lhs[i],rhs[i])
+    table.insert(result,v)
+  end
+
+  return result
+end
+
+function M.tap(f)
+  return function(...)
+    f(...)
+    return ...
+  end
+end
+
+function M.fold(mempty,mappend,tbl)
+	local result = mempty
+	for i = 1,#tbl do result = mappend(result,tbl) end
+	return result
+end
+
+function M.flatten(tbl)
+	if type(tbl) ~= 'table' then return tbl end
+	return M.fold({}, M.concat, fmap(M.flatten, tbl))
+end
+
+function M.concat(lhs,rhs)
+  local result = {}
+  for i = 1,#lhs do result[i] = lhs[i] end
+  for i = 1,#rhs do result[i + #lhs] = rhs[i] end
+  return result
+end
+
+function M.find(list,pred)
+  for i = 1,#list do
+    if pred(list[i]) then return list[i],i end
+  end
+  return nil,nil
+end
+
+function M.range(f,t,s)
+  local res = {}
+  for x = f,t,s or 1 do table.insert(res,x) end
+  return res
+end
+
+function M.image(a,b,c,d,x) return (x - a)/(b - a)*(d - c) + c end
+
+function M.apply(f,...) return f(...) end
+
+function M.once(f)
+  local ret
+  local called = false
+  return function(...)
+    if not called then
+      ret = f(...)
+      called = true
+      return ret
+    end
+  end
+end
+
+return M
diff --git a/lib/graphviz.lua b/lib/graphviz.lua
new file mode 100644
index 0000000..173612d
--- /dev/null
+++ b/lib/graphviz.lua
@@ -0,0 +1,48 @@
+--
+-- melisma - extensible and scriptable audio engine
+-- Copyright (C) 2026  Ludvig Gunne Lindström
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+--
+
+local module = {}
+
+function module.render(layout)
+  local lines = {}
+
+  local function append(format,...)
+    local line = string.format(format,...)
+    table.insert(lines,line)
+  end
+
+  append('digraph {')
+  append('rankdir=BT')
+  append('node [shape=rect]')
+
+  for id,node in pairs(layout) do
+    append('"%s" [label="%s"]',id,node.label or '?')
+  end
+
+  for id,node in pairs(layout) do
+    for _,input in ipairs(node.inputs) do
+      append('"%s" -> "%s"',input,id)
+    end
+  end
+
+  append('}')
+
+  return table.concat(lines,'\n')
+end
+
+return module
diff --git a/lib/ladspa_interface.lua b/lib/ladspa_interface.lua
new file mode 100644
index 0000000..794f431
--- /dev/null
+++ b/lib/ladspa_interface.lua
@@ -0,0 +1,63 @@
+--
+-- melisma - extensible and scriptable audio engine
+-- Copyright (C) 2026  Ludvig Gunne Lindström
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+--
+
+local m_ladspa = require 'melisma.ladspa'
+
+local M = {}
+
+function M.init(spec,...)
+	local interface = {}
+	local info = m_ladspa.info(spec)
+	local instance = m_ladspa.load(spec,...)
+	local audio_index = 1
+	local control_index = 1
+
+	for _,port in ipairs(info.ports) do
+		if port.type == 'control' and port.direction == 'input' then
+			local control_index_copy = control_index
+
+			interface[port.name] = function(self,value)
+				if port.hints.upper_bound and value > port.hints.upper_bound then
+					value = port.hints.upper_bound
+				end
+
+				if port.hints.lower_bound and value < port.hints.lower_bound then
+					value = port.hints.lower_bound
+				end
+
+				instance:control(control_index_copy,value)
+				return self
+			end
+
+			if port.hints.default then
+				interface[port.name](nil,port.hints.default)
+			end
+
+			control_index = control_index + 1
+		end
+
+		if port.type == 'audio' and port.direction == 'output' then
+			interface[port.name] = instance(audio_index)
+			audio_index = audio_index + 1
+		end
+	end
+
+	return interface
+end
+
+return M
diff --git a/lib/lazy.lua b/lib/lazy.lua
new file mode 100644
index 0000000..144ea3a
--- /dev/null
+++ b/lib/lazy.lua
@@ -0,0 +1,24 @@
+--
+-- melisma - extensible and scriptable audio engine
+-- Copyright (C) 2026  Ludvig Gunne Lindström
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+--
+
+return setmetatable({}, {
+  __index = function(tbl,key)
+    tbl[key] = require('melisma.'..key)
+    return tbl[key]
+  end
+})
diff --git a/lib/midimap.lua b/lib/midimap.lua
new file mode 100644
index 0000000..f9f7a1d
--- /dev/null
+++ b/lib/midimap.lua
@@ -0,0 +1,34 @@
+--
+-- melisma - extensible and scriptable audio engine
+-- Copyright (C) 2026  Ludvig Gunne Lindström
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+--
+
+local M = {}
+
+local function optget(map,key)
+	if map ~= nil then return nil end
+	if map[key] ~= nil then key = 'default' end
+	return map[key]
+end
+
+function M.lookup(map,msg)
+	map = optget(map,msg.status)
+	map = optget(map,msg.data1)
+	map = optget(map,msg.data2)
+	return map
+end
+
+return M
diff --git a/lib/osc.lua b/lib/osc.lua
new file mode 100644
index 0000000..66f378a
--- /dev/null
+++ b/lib/osc.lua
@@ -0,0 +1,76 @@
+--
+-- melisma - extensible and scriptable audio engine
+-- Copyright (C) 2026  Ludvig Gunne Lindström
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+--
+
+local M = {}
+
+function M.decode(data)
+  local addr,ttag,offset = string.unpack('!4 z Xs4 z Xs4',data)
+  if offset == nil then error('invalid osc message') end
+
+  ttag = string.sub(ttag,2)
+  data = string.sub(data,offset)
+
+  local args = {}
+  for i = 1,#ttag do
+    local format
+    local c = string.sub(ttag,i,i)
+
+    if c == 's' then format = '!4 z Xs4'
+    elseif c == 'i' then format = '>i4'
+    elseif c == 'f' then format = '>f'
+    else error('invalid osc message') end
+
+    local arg,offset = string.unpack(format,data)
+    if offset == nil then error('invalid osc message') end
+
+    table.insert(args,arg)
+    data = string.sub(data,offset)
+  end
+
+  return {addr=addr, args=args}
+end
+
+function M.encode(msg)
+  local addr = msg.addr
+  local args = msg.args
+  local data = ''
+  local ttag = ','
+
+  for _,arg in pairs(args) do
+    if type(arg) == 'string' then
+      ttag = ttag..'s'
+      data = data..string.pack('!4 z Xs4',arg)
+    elseif type(arg) == 'number' then
+      if math.type(arg) == 'integer' then
+        ttag = ttag..'i'
+        data = data..string.pack('>i4',arg)
+      elseif math.type(arg) == 'float' then
+        ttag = ttag..'f'
+        data = data..string.pack('>f',arg)
+      else
+        error('unsupported argument type '..math.type(arg))
+      end
+    else
+      error('unsupported argument type '..type(arg))
+    end
+  end
+
+  return string.pack('!4 z Xs4',addr)..string.pack('!4 z Xs4',ttag)..data
+end
+
+return M
diff --git a/lib/util.lua b/lib/util.lua
new file mode 100644
index 0000000..3ceb4cf
--- /dev/null
+++ b/lib/util.lua
@@ -0,0 +1,139 @@
+--
+-- melisma - extensible and scriptable audio engine
+-- Copyright (C) 2026  Ludvig Gunne Lindström
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+--
+
+local M = {}
+
+function M.deepstring(value,visited,depth,is_key)
+  if not is_key and type(value) == 'string' then return '\'' .. value .. '\'' end
+  if type(value) ~= 'table' then return tostring(value) end
+  if next(value) == nil then return '{}' end
+
+  visited = visited or {}
+  visited[value] = true
+
+  depth = depth or 0
+  local indent = string.rep('  ',depth)
+
+  local str = {}
+  local function append(...) table.insert(str,string.format(...)) end
+
+  append('{ ')
+  for k,v in pairs(value) do
+    if visited[k] then k='{...}' else k=M.deepstring(k,visited,depth+1,true) end
+    if visited[v] then v='{...}' else v=M.deepstring(v,visited,depth+1) end
+    append(indent .. '  ' .. '%s = %s, ',k,v)
+  end
+
+  append(indent .. '}')
+  return table.concat(str,'\n')
+end
+
+function M.deepcopy(x)
+  if type(x) ~= 'table' then return x end
+  local copy = {}
+  for k,v in pairs(x) do copy[k] = M.deepcopy(v) end
+  return copy
+end
+
+function M.size(x)
+  local s = 0
+  for _,_ in pairs(x) do
+    s = s + 1
+  end
+  return s
+end
+
+function M.image(a,b,c,d,x) return (x - a)/(b - a)*(d - c) + c end
+
+function M.select(list,prompt)
+  for i,entry in ipairs(list) do
+    print(i,entry)
+  end
+
+  while true do
+    io.write(prompt .. '> ')
+    io.flush()
+
+    local input = io.read('*l')
+    local i = tonumber(input)
+
+    if i == nil then
+      print()
+      error()
+    end
+
+    if i >= 1 and i <= #list then
+      return list[i]
+    end
+  end
+end
+
+function M.splitcmd(str)
+  local words = {}
+  local word = ''
+  local state = 'skip'
+
+  for i = 1,#str do
+    local c = string.sub(str,i,i)
+
+    if state == 'skip' then
+      if c == '"' then
+        state = 'string'
+      elseif c ~= ' ' then
+        state = 'take'
+        word = word .. c
+      end
+    elseif state == 'take' then
+      if c == ' ' then
+        state = 'skip'
+        table.insert(words,word)
+        word = ''
+      elseif c == '"' then
+        state = 'string'
+      else
+        word = word .. c
+      end
+    elseif state == 'string' then
+      if c == '"' then
+        state = 'take'
+      else
+        word = word .. c
+      end
+    end
+  end
+
+  if state ~= 'skip' then
+    table.insert(words,word)
+  end
+
+  return words
+end
+
+function M.openmodule(module)
+  if module.lazy_require_getmodule ~= nil then
+    module = module.lazy_require_getmodule()
+  end
+
+  for k,v in pairs(module) do
+    if string.sub(k,1,2) ~= '__' then
+      _G[k] = v
+    end
+  end
+end
+
+return M
diff --git a/mod/biquad.c b/mod/biquad.c
new file mode 100644
index 0000000..6591d87
--- /dev/null
+++ b/mod/biquad.c
@@ -0,0 +1,202 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <math.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define LOWPASS_TYPENAME "biquad LPF"
+#define LOWPASS_DEFAULT_CUTOFF 4000
+#define LOWPASS_DEFAULT_RESONANCE 0.5
+
+struct biquad;
+
+typedef void (*recomp_fn)(struct biquad*);
+
+struct biquad
+{
+	ml_channel *out;
+	recomp_fn   recomp;
+	double      x_1,x_2,y_1,y_2;
+	double      xc_0,xc_1,xc_2;
+	double      yc_1,yc_2;
+	double      Fs;
+	double      f0;
+	double      Q;
+};
+
+static inline void lowpass_recomp(struct biquad *bq)
+{
+	double w0,cosw0,sinw0,alpha,b0,b1,b2,a0,a1,a2;
+	w0 = 2*M_PI*bq->f0/bq->Fs;
+	cosw0 = cos(w0);
+	sinw0 = sin(w0);
+	alpha = sinw0/(2*bq->Q);
+	b0 = (1 - cosw0)/2;
+	b1 = 1 - cosw0;
+	b2 = (1 - cosw0)/2;
+	a0 = 1 + alpha;
+	a1 = -2*cosw0;
+	a2 = 1 - alpha;
+	bq->xc_0 = b0/a0;
+	bq->xc_1 = b1/a0;
+	bq->xc_2 = b2/a0;
+	bq->yc_1 = a1/a0;
+	bq->yc_2 = a2/a0;
+}
+
+static void proc(const ml_proc_args *args)
+{
+	struct biquad bq = *(struct biquad*) args->userp;
+
+	float *x = args->in[0];
+	float *y = args->out[0];
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		y[i] = bq.xc_0*x[i]
+		     + bq.xc_1*bq.x_1
+		     + bq.xc_2*bq.x_2
+		     - bq.yc_1*bq.y_1
+		     - bq.yc_2*bq.y_2;
+
+		bq.x_2 = bq.x_1;
+		bq.x_1 = x[i];
+		bq.y_2 = bq.y_1;
+		bq.y_1 = y[i];
+	}
+
+	*(struct biquad*) args->userp = bq;
+}
+
+static int l_lowpass_init(lua_State *s)
+{
+	ml_channel *src = mutil_get_channel(s,1);
+
+	struct biquad *bq = calloc(1,sizeof(*bq));
+	bq->recomp = lowpass_recomp;
+	bq->Fs = ml_sample_rate();
+	bq->f0 = LOWPASS_DEFAULT_CUTOFF;
+	bq->Q = LOWPASS_DEFAULT_RESONANCE;
+	bq->recomp(bq);
+
+	ml_node *node = ml_create_node(proc,bq);
+	ml_label_node(node,"lowpass");
+
+	ml_channel *dst = ml_add_input(node);
+	ml_connect(src,dst);
+
+	bq->out = ml_add_output(node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = bq;
+	luaL_setmetatable(s,LOWPASS_TYPENAME);
+
+	return 1;
+}
+
+static int l_lowpass_resonance(lua_State *s)
+{
+	struct biquad *bq = *(void**) luaL_checkudata(s,1,LOWPASS_TYPENAME);
+	bq->Q = luaL_checknumber(s,2);
+	bq->recomp(bq);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = bq;
+	luaL_setmetatable(s,LOWPASS_TYPENAME);
+	return 1;
+}
+
+static int l_lowpass_cutoff(lua_State *s)
+{
+	struct biquad *bq = *(void**) luaL_checkudata(s,1,LOWPASS_TYPENAME);
+	bq->f0 = luaL_checknumber(s,2);
+	bq->recomp(bq);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = bq;
+	luaL_setmetatable(s,LOWPASS_TYPENAME);
+	return 1;
+}
+
+static int l_lowpass_out(lua_State *s)
+{
+	struct biquad *bq = *(void**) luaL_checkudata(s,1,LOWPASS_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = bq->out;
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_biquad(lua_State *s)
+{
+/*** Digital biquad filters.
+@module biquad
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Lowpass filter.
+@type biquad.lowpass
+@usage
+
+	local mbiquad = require 'melisma.biquad'
+	local input = ...
+	local lowpass = mbiquad.lowpass.init(node, 2000, 0.6)
+	lowpass:resonance(1000)
+	lowpass:cutoff(0.25)
+*/
+	lua_newtable(s);
+	int lowpass_tbl = lua_gettop(s);
+
+/*** Create a lowpass filter.
+@static
+@function init
+@tparam channel input Input signal.
+@treturn biquad.lowpass The newly created lowpass filter.
+*/
+	lua_pushcfunction(s,l_lowpass_init);
+	lua_setfield(s,lowpass_tbl,"init");
+
+/*** Set filter resonance.
+@function lowpass:resonance
+@tparam number res Resonance.
+*/
+	lua_pushcfunction(s,l_lowpass_resonance);
+	lua_setfield(s,lowpass_tbl,"resonance");
+
+
+/*** Set filter cutoff frequency.
+@function lowpass:cutoff
+@tparam number cut Cutoff frequency.
+*/
+	lua_pushcfunction(s,l_lowpass_cutoff);
+	lua_setfield(s,lowpass_tbl,"cutoff");
+
+	lua_pushcfunction(s,l_lowpass_out);
+	lua_setfield(s,lowpass_tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,LOWPASS_TYPENAME);
+	int lowpass_mt = lua_gettop(s);
+
+	lua_pushvalue(s,lowpass_tbl);
+	lua_setfield(s,lowpass_mt,"__index");
+
+	lua_pushvalue(s,lowpass_tbl);
+	lua_setfield(s,tbl,"lowpass");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/buffer.c b/mod/buffer.c
new file mode 100644
index 0000000..64ba13e
--- /dev/null
+++ b/mod/buffer.c
@@ -0,0 +1,281 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define BUFFER_TYPENAME "buffer"
+
+enum mode {CAPTURE,PLAYBACK,IDLE};
+
+struct buffer
+{
+	ml_channel *chan;
+	enum mode   mode;
+	double      phase;
+	double      speed;
+	size_t      len;
+	size_t      cap;
+	float       data[];
+};
+
+static size_t capture(struct buffer *b, const float *in, size_t n)
+{
+	size_t i = 0;
+
+	for (; i < n; i++)
+	{
+		b->data[b->len++] = in[i];
+
+		if (b->len == b->cap)
+		{
+			b->mode = IDLE;
+			b->phase = 0;
+			break;
+		}
+	}
+
+	return i;
+}
+
+static size_t playback(struct buffer *b, float *out, size_t n)
+{
+	size_t i = 0;
+
+	for (; i < n; i++)
+	{
+		float t = b->phase*b->len;
+		size_t i0 = (size_t) t;
+		size_t i1 = i0 + 1;
+		float ip = t - i0;
+
+		i0 %= b->len;
+		i1 %= b->len;
+
+		float s0 = b->data[i0];
+		float s1 = b->data[i1];
+
+		out[i] = s0 + ip*(s1 - s0);
+
+		b->phase += b->speed/b->len;
+
+		if (b->phase >= 1)
+		{
+			b->phase = 0;
+			b->mode = IDLE;
+		}
+	}
+
+	return i;
+}
+
+static size_t idle(struct buffer *b, float *out, size_t n)
+{
+	memset(out,0,sizeof(*out)*n);
+	return n;
+}
+
+static void proc(const ml_proc_args *args)
+{
+	struct buffer *b = args->userp;
+	const float *in = args->in[0];
+	float *out = args->out[0];
+	size_t n = args->nframes;
+
+	while (n > 0)
+	{
+		size_t d;
+
+		switch (b->mode)
+		{
+		case CAPTURE:
+			d = capture(b,in,n);
+			break;
+		case PLAYBACK:
+			d = playback(b,out,n);
+			break;
+		case IDLE:
+			d = idle(b,out,n);
+			break;
+		}
+
+		in += d;
+		out += d;
+		n -= d;
+	}
+}
+
+static int l_init(lua_State *s)
+{
+	float t = luaL_checknumber(s,1);
+	ml_channel *src = mutil_get_channel(s,2);
+
+	if (t <= 0)
+	{
+		luaL_error(s,"invalid buffer capacity %.2f\n",t);
+	}
+
+	size_t sr = ml_sample_rate();
+	size_t cap = t*sr;
+
+	struct buffer *b;
+	size_t size = sizeof(*b) + sizeof(*b->data)*cap;
+	b = calloc(1,size);
+
+	ml_node *node = ml_create_node(proc,b);
+	ml_label_node(node,"buffer");
+
+	ml_channel *dst = ml_add_input(node);
+	ml_connect(src,dst);
+
+	b->mode = IDLE;
+	b->len  = 0;
+	b->phase = 0;
+	b->cap  = cap;
+	b->chan = ml_add_output(node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = b;
+	luaL_setmetatable(s,BUFFER_TYPENAME);
+
+	return 1;
+}
+
+static int l_setmode(lua_State *s)
+{
+	int mode_i = lua_upvalueindex(1);
+	struct buffer *b = *(void**) luaL_checkudata(s,1,BUFFER_TYPENAME);
+	enum mode mode = lua_tointeger(s,mode_i);
+	b->phase = 0;
+	b->mode = mode;
+
+	if (mode == CAPTURE)
+	{
+		b->len = 0;
+	}
+
+	return 0;
+}
+
+static int l_setspeed(lua_State *s)
+{
+	struct buffer *b = *(void**) luaL_checkudata(s,1,BUFFER_TYPENAME);
+	double speed = luaL_checknumber(s,2);
+
+	if (speed <= 0)
+	{
+		luaL_error(s,"invalid speed %.2f",speed);
+	}
+
+	b->speed = speed;
+	return 0;
+}
+
+static int l_getlength(lua_State *s)
+{
+	struct buffer *b = *(void**) luaL_checkudata(s,1,BUFFER_TYPENAME);
+	size_t sr = ml_sample_rate();
+	lua_pushnumber(s,(float)b->len / (float)sr / b->speed);
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct buffer *b = *(void**) luaL_checkudata(s,1,BUFFER_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = b->chan;
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_buffer(lua_State *s)
+{
+/*** Audio buffer for capture/playback.
+
+	local mbuffer = require 'melisma.buffer'
+	local mevent = require 'melisma.event'
+
+	local input = ...
+
+	-- Create a buffer with capacity of 5 seconds
+	-- Capture stops automatically when buffer is full.
+	local len = 5
+	local buffer = mbuffer.init(input, len)
+
+	-- Capture audio
+	buffer:capture()
+
+	-- Playback after capture 3 seconds
+	mevent.schedule(3, buffer.playback, buffer)
+
+@classmod buffer
+*/
+	lua_newtable(s);
+	int tbl = lua_absindex(s,lua_gettop(s));
+
+/*** Create an audio buffer.
+@static
+@function buffer.init
+@tparam channel input Input signal.
+@tparam number len Buffer capacity in seconds.
+@treturn buffer The newly created audio buffer.
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+/*** Set playback speed.
+@function buffer.speed
+@tparam number speed Playback speed.
+*/
+	lua_pushcfunction(s,l_setspeed);
+	lua_setfield(s,tbl,"speed");
+
+/*** Get length of captured audio.
+@function buffer.length
+@treturn number Length of captured audio in seconds.
+*/
+	lua_pushcfunction(s,l_getlength);
+	lua_setfield(s,tbl,"length");
+
+/*** Start playback mode.
+@function buffer.playback
+*/
+	lua_pushinteger(s,PLAYBACK);
+	lua_pushcclosure(s,l_setmode,1);
+	lua_setfield(s,tbl,"playback");
+
+/*** Start capture mode.
+@function buffer.capture
+*/
+	lua_pushinteger(s,CAPTURE);
+	lua_pushcclosure(s,l_setmode,1);
+	lua_setfield(s,tbl,"capture");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,BUFFER_TYPENAME);
+	int mt = lua_absindex(s,lua_gettop(s));
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/delay.c b/mod/delay.c
new file mode 100644
index 0000000..44441cf
--- /dev/null
+++ b/mod/delay.c
@@ -0,0 +1,233 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define DELAY_TYPENAME "delay"
+
+#define MAX_DELAY         2.00f
+#define DEFAULT_DELAY     0.25f
+#define DEFAULT_GAIN      1.00f
+#define DEFAULT_FEEDBACK  0.25f
+#define DEFAULT_WETDRYMIX 0.50f
+
+#define CLAMP(v,min,max) ((v)<(min)?(min):((v)>(max)?(max):(v)))
+
+struct delay
+{
+	ml_channel *out;
+	float       feedback;
+	float       gain;
+	float       wetdrymix;
+	float       delay;
+	size_t      len;
+	size_t      write;
+	float      *buffer;
+};
+
+static void proc(const ml_proc_args *args)
+{
+	struct delay *dl = args->userp;
+
+	size_t sr = ml_sample_rate();
+	size_t offset = sr*dl->delay;
+
+	const float *in = args->in[0];
+	float *out = args->out[0];
+
+	size_t read;
+	float dry,wet;
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		read = dl->write + dl->len - offset;
+
+		if (read >= dl->len)
+		{
+			read -= dl->len;
+		}
+
+		dry = in[i];
+		wet = dl->buffer[read]*dl->gain;
+
+		out[i] = wet*dl->wetdrymix + dry*(1 - dl->wetdrymix);
+		dl->buffer[dl->write++] = dry + wet*dl->feedback;
+
+		if (dl->write == dl->len)
+		{
+			dl->write = 0;
+		}
+	}
+}
+
+static void clamp(struct delay *dl)
+{
+	dl->delay = CLAMP(dl->delay,0,MAX_DELAY);
+	dl->gain = CLAMP(dl->gain,0,1);
+	dl->feedback = CLAMP(dl->feedback,0,1);
+	dl->wetdrymix = CLAMP(dl->wetdrymix,0,1);
+}
+
+static int l_init(lua_State *s)
+{
+	ml_channel *src = mutil_get_channel(s,1);
+
+	struct delay *dl = calloc(1,sizeof(*dl));
+
+	dl->delay = DEFAULT_DELAY;
+	dl->gain = DEFAULT_GAIN;
+	dl->feedback = DEFAULT_FEEDBACK;
+	dl->wetdrymix = DEFAULT_WETDRYMIX;
+
+	size_t sr = ml_sample_rate();
+	dl->len = sr*MAX_DELAY;
+	dl->buffer = calloc(1,dl->len*sizeof(dl->buffer[0]));
+
+	clamp(dl);
+
+	ml_node *node = ml_create_node(proc,dl);
+	ml_label_node(node,"delay");
+	ml_channel *dst = ml_add_input(node);
+	ml_connect(src,dst);
+
+	dl->out = ml_add_output(node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = dl;
+	luaL_setmetatable(s,DELAY_TYPENAME);
+
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct delay *dl = *(void**) luaL_checkudata(s,1,DELAY_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = dl->out;
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+static int l_delay(lua_State *s)
+{
+	struct delay *dl = *(void**) luaL_checkudata(s,1,DELAY_TYPENAME);
+	float v = luaL_checknumber(s,2);
+	dl->delay = v;
+	clamp(dl);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = dl;
+	luaL_setmetatable(s,DELAY_TYPENAME);
+	return 1;
+}
+
+static int l_gain(lua_State *s)
+{
+	struct delay *dl = *(void**) luaL_checkudata(s,1,DELAY_TYPENAME);
+	float v = luaL_checknumber(s,2);
+	dl->gain = v;
+	clamp(dl);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = dl;
+	luaL_setmetatable(s,DELAY_TYPENAME);
+	return 1;
+}
+
+static int l_feedback(lua_State *s)
+{
+	struct delay *dl = *(void**) luaL_checkudata(s,1,DELAY_TYPENAME);
+	float v = luaL_checknumber(s,2);
+	dl->feedback = v;
+	clamp(dl);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = dl;
+	luaL_setmetatable(s,DELAY_TYPENAME);
+	return 1;
+}
+
+static int l_wetdrymix(lua_State *s)
+{
+	struct delay *dl = *(void**) luaL_checkudata(s,1,DELAY_TYPENAME);
+	float v = luaL_checknumber(s,2);
+	dl->wetdrymix = v;
+	clamp(dl);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = dl;
+	luaL_setmetatable(s,DELAY_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_delay(lua_State *s)
+{
+	ml_check_version();
+
+/*** Digital delay line.
+@classmod delay
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Create a delay line.
+@static
+@function init
+@tparam channel input Input signal.
+@treturn delay Newly created delay line.
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+/*** Set delay.
+@function delay
+@tparam number d delay in seconds.
+@treturn delay
+*/
+	lua_pushcfunction(s,l_delay);
+	lua_setfield(s,tbl,"delay");
+
+/*** Set gain.
+@function gain
+@tparam number g Gain (**TODO**: Use decibels).
+@treturn delay
+*/
+	lua_pushcfunction(s,l_gain);
+	lua_setfield(s,tbl,"gain");
+
+/*** Set feedback.
+@function feedback
+@tparam number f Feedback.
+@treturn delay
+*/
+	lua_pushcfunction(s,l_feedback);
+	lua_setfield(s,tbl,"feedback");
+
+/*** Set wet/dry mix.
+@function wetdrymix
+@tparam number wd Wet/dry mix.
+@treturn delay
+*/
+	lua_pushcfunction(s,l_wetdrymix);
+	lua_setfield(s,tbl,"wetdrymix");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,DELAY_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/expression.c b/mod/expression.c
new file mode 100644
index 0000000..1b78199
--- /dev/null
+++ b/mod/expression.c
@@ -0,0 +1,500 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <assert.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define EXPR_TYPENAME "expression"
+#define SCRIPT_TYPENAME "expression script"
+
+enum tag {ADD,SUB,MUL,DIV,IN,OUT,CONST,HALT};
+
+struct op
+{
+	enum tag    tag;
+	float       value;
+	size_t      index;
+	size_t      offset;
+	ml_channel *src;
+};
+
+struct script
+{
+	size_t    len;
+	struct op ops[];
+};
+
+struct expr
+{
+	size_t           num_inputs;
+	size_t          *buf_lens;
+	size_t          *cursors;
+	float          **bufs;
+	size_t           out_buf_len;
+	size_t           out_cursor;
+	float           *out_buf;
+	float           *stack;
+	size_t           stack_len;
+	size_t           stack_p;
+	struct script   *script;
+	ml_channel      *out;
+};
+
+static size_t script_alloc_size(size_t len)
+{
+	return sizeof(struct script) + len*sizeof(struct op);
+}
+
+static struct script *push_script(lua_State *s, size_t len)
+{
+	struct script *script = lua_newuserdata(s,script_alloc_size(len));
+	luaL_setmetatable(s,SCRIPT_TYPENAME);
+	script->len = len;
+	return script;
+}
+
+static int l_const(lua_State *s)
+{
+	float value = luaL_checknumber(s,1);
+	struct script *script = push_script(s,1);
+	script->ops[0].tag = CONST;
+	script->ops[0].value = value;
+	return 1;
+}
+
+static int l_input(lua_State *s)
+{
+	ml_channel *src = mutil_get_channel(s,1);
+	size_t offset = luaL_optinteger(s,2,0);
+	struct script *script = push_script(s,1);
+	script->ops[0].tag = IN;
+	script->ops[0].src = src;
+	script->ops[0].offset = offset;
+	return 1;
+}
+
+static int l_output(lua_State *s)
+{
+	size_t offset = luaL_checkinteger(s,1);
+	struct script *script = push_script(s,1);
+	script->ops[0].tag = OUT;
+	script->ops[0].offset = offset;
+	return 1;
+}
+
+static int convert(lua_State *s, int i)
+{
+	if (luaL_testudata(s,i,SCRIPT_TYPENAME))
+	{
+		return i;
+	}
+
+	if (lua_isnumber(s,i))
+	{
+		lua_pushcfunction(s,l_const);
+		lua_pushvalue(s,i);
+		lua_call(s,1,1);
+		return lua_gettop(s);
+	}
+
+	const char *typename = lua_typename(s,lua_type(s,i));
+	luaL_error(s,"expected number or expression script, got %s",typename);
+
+	return 0;
+}
+
+static int binop(lua_State *s, int tag)
+{
+	int lhs_i = convert(s,1);
+	int rhs_i = convert(s,2);
+
+	struct script *lhs = luaL_checkudata(s,lhs_i,SCRIPT_TYPENAME);
+	struct script *rhs = luaL_checkudata(s,rhs_i,SCRIPT_TYPENAME);
+
+	size_t len = lhs->len + rhs->len + 1;
+	struct script *res = push_script(s,len);
+
+	memcpy(&res->ops[0],lhs->ops,sizeof(res->ops[0])*lhs->len);
+	memcpy(&res->ops[lhs->len],rhs->ops,sizeof(res->ops[0])*rhs->len);
+
+	res->ops[len-1].tag = tag;
+
+	return 1;
+}
+
+static int l_add(lua_State *s)
+{
+	return binop(s,ADD);
+}
+
+static int l_sub(lua_State *s)
+{
+	return binop(s,SUB);
+}
+
+static int l_mul(lua_State *s)
+{
+	return binop(s,MUL);
+}
+
+static int l_div(lua_State *s)
+{
+	return binop(s,DIV);
+}
+
+static void prepare_inputs(ml_node *node, struct script *script, size_t **buf_lens)
+{
+	for (size_t i = 0; i < script->len; i++)
+	{
+		struct op *op = &script->ops[i];
+
+		if (op->tag != IN)
+		{
+			continue;
+		}
+
+		/* the same input channel may have been encountered already */
+		bool have_prev = false;
+		for (size_t j = 0; j < i; j++)
+		{
+			struct op *prev = &script->ops[j];
+
+			if (prev->tag != IN)
+			{
+				continue;
+			}
+
+			if (op->src == prev->src)
+			{
+				op->index = prev->index;
+				have_prev = true;
+
+				if (op->offset+1 > (*buf_lens)[op->index])
+				{
+					/* grow lookback buffer length */
+					(*buf_lens)[op->index] = op->offset+1;
+				}
+
+				break;
+			}
+		}
+
+		if (have_prev)
+		{
+			continue;
+		}
+
+		op->index = ml_num_inputs(node);
+		ml_channel *dst = ml_add_input(node);
+		ml_connect(op->src,dst);
+
+		/* add buffer length */
+		*buf_lens = realloc(*buf_lens,sizeof(**buf_lens)*ml_num_inputs(node));
+		(*buf_lens)[op->index] = op->offset+1;
+	}
+}
+
+static size_t max_output_offset(struct script *script)
+{
+	size_t max = 0;
+
+	for (size_t i = 0; i < script->len; i++)
+	{
+		struct op *op = &script->ops[i];
+
+		if (op->tag != OUT)
+		{
+			continue;
+		}
+
+		if (op->offset+1 > max)
+		{
+			max = op->offset+1;
+		}
+	}
+
+	return max;
+}
+
+static void proc(const ml_proc_args *args);
+
+static int l_build(lua_State *s)
+{
+	struct script *script = luaL_checkudata(s,1,SCRIPT_TYPENAME);
+
+	/* copy script and add a halt instruction */
+	struct script *copy = calloc(1,script_alloc_size(script->len+1));
+	copy->len = script->len + 1;
+	memcpy(copy->ops,script->ops,script->len*sizeof(copy->ops[0]));
+	copy->ops[script->len].tag = HALT;
+
+	struct expr *expr = calloc(1,sizeof(*expr));
+	expr->script = copy;
+
+	/* add output channel */
+	ml_node *node = ml_create_node(proc,expr);
+	ml_label_node(node,"expression");
+	expr->out = ml_add_output(node);
+
+	/* set input ops indices and determine lookback buffer lengths */
+	prepare_inputs(node,copy,&expr->buf_lens);
+	expr->num_inputs = ml_num_inputs(node);
+
+	/* allocate lookback buffers for inputs */
+	expr->bufs = calloc(1,sizeof(*expr->bufs)*expr->num_inputs);
+	expr->cursors = calloc(1,sizeof(*expr->cursors)*expr->num_inputs);
+	for (size_t i = 0; i < expr->num_inputs; i++)
+	{
+		expr->bufs[i] = calloc(1,sizeof(*expr->bufs[i])*expr->buf_lens[i]);
+	}
+
+	/* allocate lookback buffer for output */
+	expr->out_buf_len = max_output_offset(copy);
+	expr->out_buf = calloc(1,sizeof(*expr->out_buf)*expr->out_buf_len);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = expr;
+	luaL_setmetatable(s,EXPR_TYPENAME);
+
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct expr *e = *(void**) luaL_checkudata(s,1,EXPR_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = e->out;
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+static void push(struct expr *expr, float v)
+{
+	if (expr->stack_p == expr->stack_len)
+	{
+		expr->stack_len = expr->stack_len == 0 ? 12 : 2*expr->stack_len;
+		expr->stack = realloc(expr->stack,sizeof(expr->stack[0])*expr->stack_len);
+	}
+
+	expr->stack[expr->stack_p++] = v;
+}
+
+static float pop(struct expr *expr)
+{
+	assert(expr->stack_p > 0);
+	return expr->stack[--expr->stack_p];
+}
+
+static void proc(const ml_proc_args *args)
+{
+	struct expr *e = args->userp;
+
+	static const void *tbl[] = {
+		[ADD] = &&op_add,
+		[SUB] = &&op_sub,
+		[MUL] = &&op_mul,
+		[DIV] = &&op_div,
+		[IN] = &&op_in,
+		[OUT] = &&op_out,
+		[CONST] = &&op_const,
+		[HALT] = &&op_halt,
+	};
+
+	float *out = args->out[0];
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		/* update lookback buffers */
+		for (size_t j = 0; j < e->num_inputs; j++)
+		{
+			e->bufs[j][e->cursors[j]] = args->in[j][i];
+		}
+
+		/* execute script */
+		size_t pc = 0;
+		struct op *op;
+		float rhs,lhs,res;
+		size_t l;
+
+		#define NEXT()\
+			op = &e->script->ops[pc++];\
+			goto *tbl[op->tag];
+
+		NEXT();
+
+		op_add:
+			rhs = pop(e);
+			lhs = pop(e);
+			push(e,lhs+rhs);
+			NEXT();
+
+		op_sub:
+			rhs = pop(e);
+			lhs = pop(e);
+			push(e,lhs-rhs);
+			NEXT();
+
+		op_mul:
+			rhs = pop(e);
+			lhs = pop(e);
+			push(e,lhs*rhs);
+			NEXT();
+
+		op_div:
+			rhs = pop(e);
+			lhs = pop(e);
+			push(e,lhs/rhs);
+			NEXT();
+
+		op_in:
+			l = e->cursors[op->index] + e->buf_lens[op->index] - op->offset;
+			while (l >= e->buf_lens[op->index])
+			{
+				l -= e->buf_lens[op->index];
+			}
+			push(e,e->bufs[op->index][l]);
+			NEXT();
+
+		op_out:
+			l = e->out_cursor + e->out_buf_len - op->offset;
+			while (l >= e->out_buf_len)
+			{
+				l -= e->out_buf_len;
+			}
+			push(e,e->out_buf[l]);
+			NEXT();
+
+		op_const:
+			push(e,op->value);
+			NEXT();
+
+		op_halt:
+			assert(e->stack_p == 1);
+			out[i] = pop(e);
+
+		/* update output lookback buffer */
+		if (e->out_buf_len > 0)
+		{
+			e->out_buf[e->out_cursor++] = out[i];
+			if (e->out_cursor == e->out_buf_len)
+			{
+				e->out_cursor = 0;
+			}
+		}
+
+		/* update input looback buffer cursors */
+		for (size_t j = 0; j < e->num_inputs; j++)
+		{
+			e->cursors[j]++;
+			if (e->cursors[j] == e->buf_lens[j])
+			{
+				e->cursors[j] = 0;
+			}
+		}
+	}
+}
+
+int luaopen_melisma_expression(lua_State *s)
+{
+/*** Build filters with arithmetic expressions.
+
+	local mexpression = require 'melisma.expression'
+	local input = mepxression.input
+
+	local lhs = ...
+	local rhs = ...
+
+	local script = input(lhs,0) + 0.5 * input(rhs,10)
+	local expression = script:build()
+
+@module expression
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+	lua_pushcfunction(s,l_const);
+	lua_setfield(s,tbl,"const");
+
+/*** Introduce an input signal in the expression.
+@static
+@function input
+@tparam channel sig Input signal.
+@tparam integer off Offset in no. of samples.
+@treturn script
+*/
+	lua_pushcfunction(s,l_input);
+	lua_setfield(s,tbl,"input");
+
+
+/*** Introduce the output signal in the expression.
+@static
+@function output
+@tparam integer off Offset in no. of samples.
+@treturn script
+*/
+	lua_pushcfunction(s,l_output);
+	lua_setfield(s,tbl,"output");
+
+/*** Represents an expression before compilation.
+Implements `__add`, `__sub`, `__mul` and `__div` for
+combining scripts in to larger ones.
+@type script
+*/
+/*** Compile an expression script.
+@function script:build
+@treturn expression
+*/
+	lua_pushcfunction(s,l_build);
+	lua_setfield(s,tbl,"build");
+
+	luaL_newmetatable(s,SCRIPT_TYPENAME);
+	int script_mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,script_mt,"__index");
+
+	lua_pushcfunction(s,l_add);
+	lua_setfield(s,script_mt,"__add");
+
+	lua_pushcfunction(s,l_sub);
+	lua_setfield(s,script_mt,"__sub");
+
+	lua_pushcfunction(s,l_mul);
+	lua_setfield(s,script_mt,"__mul");
+
+	lua_pushcfunction(s,l_div);
+	lua_setfield(s,script_mt,"__div");
+
+	lua_newtable(s);
+	int expr_tbl = lua_gettop(s);
+
+	luaL_newmetatable(s,EXPR_TYPENAME);
+	int expr_mt = lua_gettop(s);
+
+	lua_pushvalue(s,expr_tbl);
+	lua_setfield(s,expr_mt,"__index");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,expr_tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/fs.c b/mod/fs.c
new file mode 100644
index 0000000..e08dfda
--- /dev/null
+++ b/mod/fs.c
@@ -0,0 +1,103 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <errno.h>
+#include <dirent.h>
+#include <lauxlib.h>
+
+static const char *dirent_typestr(struct dirent *de)
+{
+	switch (de->d_type)
+	{
+	case DT_BLK:  return "b";
+	case DT_CHR:  return "c";
+	case DT_DIR:  return "d";
+	case DT_FIFO: return "p";
+	case DT_REG:  return "f";
+	case DT_LNK:  return "l";
+	case DT_SOCK: return "s";
+	default:      return "?";
+	}
+}
+
+static void push_dirent(lua_State *s, struct dirent *de)
+{
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+	lua_pushstring(s,de->d_name);
+	lua_setfield(s,tbl,"name");
+
+	lua_pushstring(s,dirent_typestr(de));
+	lua_setfield(s,tbl,"type");
+
+	lua_settop(s,tbl);
+}
+
+static int l_readdir(lua_State *s)
+{
+	const char *path = luaL_checkstring(s,1);
+	DIR *dirp = opendir(path);
+
+	if (dirp == NULL)
+	{
+		luaL_error(s,strerror(errno));
+	}
+
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+	int i = 1;
+	struct dirent *de;
+	while ((de = readdir(dirp)) != NULL)
+	{
+		push_dirent(s,de);
+		lua_rawseti(s,tbl,i++);
+	}
+
+	closedir(dirp);
+	lua_settop(s,tbl);
+	return 1;
+}
+
+int luaopen_melisma_fs(lua_State *s)
+{
+/*** File system utilities.
+@module fs
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** List directory contents.
+@function readdir
+@tparam string path Directory path.
+@treturn table Directory contents.
+@usage
+local fs = require 'melisma.fs'
+local contents = fs.readdir('.')
+for _,entry in ipairs(contents) do
+	print(entry.name, entry.type)
+end
+*/
+	lua_pushcfunction(s,l_readdir);
+	lua_setfield(s,tbl,"readdir");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/gain.c b/mod/gain.c
new file mode 100644
index 0000000..994efcf
--- /dev/null
+++ b/mod/gain.c
@@ -0,0 +1,164 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include <lauxlib.h>
+
+#include "melisma.h"
+#include "mutil.h"
+
+#define GAIN_TYPENAME "gain"
+
+struct gain
+{
+	ml_node *node;
+	float    value;
+	int      mapped;
+	int      db;
+};
+
+static void proc(const ml_proc_args *args)
+{
+	struct gain *gain = args->userp;
+
+	float *in = args->in[0];
+	float *out = args->out[0];
+	float *mapped = gain->mapped ? args->in[1] :  NULL;
+	float v;
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		v = mapped ? mapped[i] : gain->value;
+
+		if (gain->db)
+		{
+			v = powf(10,v/20.f);
+		}
+
+		out[i] = v*in[i];
+	}
+}
+
+static int l_init(lua_State *s)
+{
+	int db_i = lua_upvalueindex(1);
+	int db = lua_tointeger(s,db_i);
+	ml_channel *audio_src, *mapped_src = NULL;
+	ml_channel *audio_dst, *mapped_dst;
+	float value = 0;
+
+
+	if (lua_isuserdata(s,1))
+	{
+		mapped_src = mutil_get_channel(s,1);
+	}
+	else
+	{
+		value = luaL_checknumber(s,1);
+	}
+
+	audio_src = mutil_get_channel(s,2);
+
+	struct gain *gain = calloc(1,sizeof(*gain));
+	gain->value = value;
+	gain->mapped = mapped_src != NULL;
+	gain->db = db;
+
+	ml_node *node = ml_create_node(proc,gain);
+	ml_label_node(node,"gain");
+	gain->node = node;
+
+	ml_add_output(node);
+
+	audio_dst = ml_add_input(node);
+	ml_connect(audio_src,audio_dst);
+
+	if (mapped_src)
+	{
+		mapped_dst = ml_add_input(node);
+		ml_connect(mapped_src,mapped_dst);
+	}
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = gain;
+	luaL_setmetatable(s,GAIN_TYPENAME);
+
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct gain *gain = *(void**) luaL_checkudata(s,1,GAIN_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(gain->node,0);
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_gain(lua_State *s)
+{
+	ml_check_version();
+
+/*** Apply gain to signals.
+	local mgain = require 'melisma.gain'
+
+	-- Interprets `cntl` as decibels and applies it to `input`
+	local input = ...
+	local cntl = ...
+	local gain = mgain.db(input,cntl)
+
+@classmod gain
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Creates a linear gain unit.
+@static
+@function linear
+@tparam channel input Input signal.
+@tparam number|channel gain Constant gain or a controlling signal.
+@treturn gain The newly created gain unit.
+*/
+	lua_pushinteger(s,0);
+	lua_pushcclosure(s,l_init,1);
+	lua_setfield(s,tbl,"linear");
+
+/*** Creates a decibel gain unit.
+@static
+@function db
+@tparam channel input Input signal.
+@tparam number|channel gain Constant gain in decibels or a controlling signal.
+@treturn gain The newly created gain unit.
+*/
+	lua_pushinteger(s,1);
+	lua_pushcclosure(s,l_init,1);
+	lua_setfield(s,tbl,"db");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,GAIN_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/interp.c b/mod/interp.c
new file mode 100644
index 0000000..c5bbefb
--- /dev/null
+++ b/mod/interp.c
@@ -0,0 +1,257 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define INTERP_TYPENAME "interp"
+#define DEFAULT_METHOD "linear"
+
+struct interp;
+typedef float (*smp_fn)(float);
+
+enum {
+	LINEAR,
+	EASEIN,
+	EASEOUT,
+	SMOOTHSTEP,
+};
+
+struct interp
+{
+	ml_channel *out;
+	smp_fn      smp;
+	float       src;
+	float       dst;
+	size_t      t0;
+	size_t      t;
+	int         method;
+};
+
+static float sample(struct interp *ip)
+{
+	float x = ip->t0 == 0 ? 0 : (float)ip->t / (float)ip->t0;
+	switch (ip->method)
+	{
+	case LINEAR:
+		break;
+	case EASEIN:
+		x = x*x;
+		break;
+	case EASEOUT:
+		x = 1 -x;
+		x = 1 - x*x;
+		break;
+	case SMOOTHSTEP:
+		x = x*x*(3 - 2*x);
+		break;
+	}
+	return ip->src + x*(ip->dst - ip->src);
+}
+
+static void proc(const ml_proc_args *args)
+{
+	struct interp *ip = args->userp;
+
+	float *out = args->out[0];
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		out[i] = sample(ip);
+
+		if (ip->t == ip->t0)
+		{
+			ip->t = 0;
+			ip->t0 = 0;
+			ip->src = ip->dst;
+		}
+		else
+		{
+			ip->t++;
+		}
+	}
+}
+
+static int l_init(lua_State *s)
+{
+	float v = luaL_checknumber(s,1);
+
+	struct interp *ip = calloc(1,sizeof(*ip));
+	ip->src = v;
+	ip->dst = v;
+	ip->method = LINEAR;
+
+	ml_node *node = ml_create_node(proc,ip);
+	ml_label_node(node,"interp");
+	ip->out = ml_add_output(node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ip;
+	luaL_setmetatable(s,INTERP_TYPENAME);
+
+	return 1;
+}
+
+static int l_set(lua_State *s)
+{
+	struct interp *ip = *(void**) luaL_checkudata(s,1,INTERP_TYPENAME);
+	float v = luaL_checknumber(s,2);
+
+	ip->src = v;
+	ip->dst = v;
+	ip->t0 = 0;
+	ip->t = 0;
+
+	return 0;
+}
+
+static int l_target(lua_State *s)
+{
+	int method_i = lua_upvalueindex(1);
+	int method = luaL_checkinteger(s,method_i);
+	struct interp *ip = *(void**) luaL_checkudata(s,1,INTERP_TYPENAME);
+	float v = luaL_checknumber(s,2);
+	float t = luaL_checknumber(s,3);
+
+	size_t sr = ml_sample_rate();
+
+	ip->src = sample(ip);
+	ip->dst = v;
+	ip->t0 = sr*t;
+	ip->t = 0;
+	ip->method = method;
+
+	return 0;
+}
+
+static int l_sample(lua_State *s)
+{
+	struct interp *ip = *(void**) luaL_checkudata(s,1,INTERP_TYPENAME);
+	lua_pushnumber(s,sample(ip));
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct interp *ip = *(void**) luaL_checkudata(s,1,INTERP_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ip->out;
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_interp(lua_State *s)
+{
+	ml_check_version();
+
+/*** Interpolation.
+
+	local minterp = require 'melisma.interp'
+	local mevent = require 'melisma.event'
+	local mgain = require 'melisma.gain'
+
+	local interp = minterp.init(0)
+
+	interp:linear(1,1)
+
+	mevent.schedule(0.5, function()
+		print('current value:', interp:sample())
+	end)
+
+	local sig = ...
+	local gain = mgain.linear(sig,interp)
+
+@classmod interp
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Initialize an interpolation unit.
+@static
+@function init
+@tparam number x0 Initial value.
+@treturn interp The newly created interpolation unit.
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+/*** Set value directly.
+@function set
+@tparam number x New value.
+*/
+	lua_pushcfunction(s,l_set);
+	lua_setfield(s,tbl,"set");
+
+/*** Interpolate using linear interpolation.
+@function linear
+@tparam number v Target value.
+@tparam number t Interpolation time.
+*/
+	lua_pushnumber(s,LINEAR);
+	lua_pushcclosure(s,l_target,1);
+	lua_setfield(s,tbl,"linear");
+
+
+/*** Interpolate using ease-in interpolation.
+@function ease_in
+@tparam number v Target value.
+@tparam number t Interpolation time.
+*/
+	lua_pushnumber(s,EASEIN);
+	lua_pushcclosure(s,l_target,1);
+	lua_setfield(s,tbl,"ease_in");
+
+
+/*** Interpolate using ease-out interpolation.
+@function ease_out
+@tparam number v Target value.
+@tparam number t Interpolation time.
+*/
+	lua_pushnumber(s,EASEOUT);
+	lua_pushcclosure(s,l_target,1);
+	lua_setfield(s,tbl,"ease_out");
+
+/*** Interpolate using smoothstep interpolation.
+@function smoothstep
+@tparam number v Target value.
+@tparam number t Interpolation time.
+*/
+	lua_pushnumber(s,SMOOTHSTEP);
+	lua_pushcclosure(s,l_target,1);
+	lua_setfield(s,tbl,"smoothstep");
+
+/*** Get the current value.
+@function sample
+@treturn number The current value.
+*/
+	lua_pushcfunction(s,l_sample);
+	lua_setfield(s,tbl,"sample");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,INTERP_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/keycallback.c b/mod/keycallback.c
new file mode 100644
index 0000000..2352cbf
--- /dev/null
+++ b/mod/keycallback.c
@@ -0,0 +1,147 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "melisma/ring.h"
+
+static int fn = LUA_NOREF;
+static struct termios tty = {0};
+static struct termios oldtty = {0};
+static lua_State *state;
+static ml_ring *ring = NULL;
+
+static void make_arg(lua_State *s, size_t len, const void *data)
+{
+	lua_pushlstring(s,data,len);
+}
+
+static void io_handler(int fd, int flags, void *args)
+{
+	char c;
+
+	if (read(fd,&c,sizeof c) <= 0)
+	{
+		return;
+	}
+
+	ml_ring_put_blocking(ring,*(uint8_t*) &c);
+}
+
+static void cleanup(void)
+{
+	tcsetattr(STDIN_FILENO,TCSANOW,&oldtty);
+}
+
+static void proc(const ml_proc_args *args)
+{
+	if (fn == LUA_NOREF)
+	{
+		return;
+	}
+
+	char buf[1];
+	while (ml_ring_read(ring,buf,sizeof buf) == sizeof buf)
+	{
+		lua_pushlstring(state,buf,sizeof buf);
+		int arg = luaL_ref(state,LUA_REGISTRYINDEX);
+		ml_schedule_event(0,fn,arg);
+	}
+}
+
+static void setup(lua_State *s)
+{
+	static bool init = false;
+
+	if (init)
+	{
+		return;
+	}
+
+	init = true;
+
+	tcgetattr(STDIN_FILENO,&oldtty);
+	tty = oldtty;
+	tty.c_lflag &= ~ECHO;
+	tty.c_lflag &= ~ICANON;
+	tcsetattr(STDIN_FILENO,TCSANOW,&tty);
+	tcflush(STDIN_FILENO,TCIFLUSH);
+
+	ml_add_io_handler(STDIN_FILENO,POLLIN,io_handler,NULL);
+	ring = ml_ring_init(4096);
+	state = s;
+
+	ml_node *node = ml_create_node(proc,NULL);
+	ml_channel *src = ml_add_output(node);
+	ml_channel *dst = ml_add_input(ml_get_root_node());
+	ml_connect(src,dst);
+	ml_label_node(node,"keycallback");
+
+	atexit(cleanup);
+}
+
+static int l_set(lua_State *s)
+{
+	if (fn != LUA_NOREF)
+	{
+		luaL_unref(s,LUA_REGISTRYINDEX,fn);
+		fn = LUA_NOREF;
+	}
+
+	if (lua_isnil(s,1))
+	{
+		return 0;
+	}
+
+	luaL_checktype(s,1,LUA_TFUNCTION);
+	lua_pushvalue(s,1);
+	fn = luaL_ref(s,LUA_REGISTRYINDEX);
+
+	setup(s);
+
+	return 0;
+}
+
+int luaopen_melisma_keycallback(lua_State *s)
+{
+/*** Set callback for keyboard input.
+	local mkeycallback = require 'melisma.keycallback'
+
+	mkeycallback.set(function(c)
+		print('you pressed', c)
+	end)
+@module keycallback
+*/
+	lua_newtable(s);
+	int tbl = lua_absindex(s,lua_gettop(s));
+
+/*** Set the callback.
+@function set
+@tparam function fn Callback function.
+*/
+	lua_pushcfunction(s,l_set);
+	lua_setfield(s,tbl,"set");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/ladspa.c b/mod/ladspa.c
new file mode 100644
index 0000000..4b681b9
--- /dev/null
+++ b/mod/ladspa.c
@@ -0,0 +1,604 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <dlfcn.h>
+#include <sys/stat.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+#include "../external/ladspa.h"
+
+#define LADSPA_TYPENAME "ladspa plugin"
+
+struct cache
+{
+	const char   *key;
+	void         *ptr;
+	struct cache *next;
+};
+
+struct ladspa
+{
+	ml_node                 *node;
+	const LADSPA_Descriptor *dsc;
+	LADSPA_Handle           *hdl;
+	float                   *cntl;
+};
+
+static struct cache *lib_cache = NULL;
+static struct cache *dsc_cache = NULL;
+
+static void *lookup(struct cache *c, const char *k)
+{
+	while (c)
+	{
+		if (strcmp(c->key,k) == 0)
+		{
+			return c->ptr;
+		}
+		c = c->next;
+	}
+	return NULL;
+}
+
+static void cache(struct cache **c, const char *k, void *p)
+{
+	struct cache *head = calloc(1,sizeof(*head));
+	head->key = strdup(k);
+	head->ptr = p;
+	head->next = *c;
+	*c = head;
+}
+
+static int exists(const char *path)
+{
+	struct stat st;
+	return stat(path,&st) == 0;
+}
+
+static const char *find_lib(const char *path)
+{
+	if (exists(path))
+	{
+		return path;
+	}
+
+	if (strchr(path,'/') != NULL)
+	{
+		return NULL;
+	}
+
+	char *lp = getenv("LADSPA_PATH");
+
+	if (lp == NULL)
+	{
+		return NULL;
+	}
+
+	lp = strdup(lp);
+	char *ptr = lp;
+	char *dir;
+
+	while ((dir = strtok(ptr,":")) != NULL)
+	{
+		ptr = NULL;
+
+		static char buf[PATH_MAX];
+		snprintf(buf,sizeof buf,"%s/%s",dir,path);
+
+		if (exists(buf))
+		{
+			free(lp);
+			return buf;
+		}
+	}
+
+	free(lp);
+
+	return NULL;
+}
+
+static void *get_lib(lua_State *s, const char *path)
+{
+	void *lib;
+
+	if ((lib = lookup(lib_cache,path)) != NULL)
+	{
+		return lib;
+	}
+
+	const char *found = find_lib(path);
+
+	if (found == NULL)
+	{
+		luaL_error(s,"failed to find library %s",path);
+	}
+
+	lib = dlopen(found,RTLD_NOW);
+
+	if (lib == NULL)
+	{
+		luaL_error(s,"failed to load library %s: %s",dlerror());
+	}
+
+	cache(&lib_cache,path,lib);
+
+	return lib;
+}
+
+static void parse_spec(lua_State *s, const char *spec, char *path, char *name)
+{
+	char buf[128];
+	strcpy(buf,spec);
+
+	const char *f;
+
+	if ((f = strtok(buf,":")) == NULL)
+	{
+		goto invalid;
+	}
+
+	strcpy(path,f);
+
+	if ((f = strtok(NULL,":")) == NULL)
+	{
+		goto invalid;
+	}
+
+	strcpy(name,f);
+
+	return;
+
+invalid:
+	luaL_error(s,"invalid ladspa spec: %s",spec);
+}
+
+static const LADSPA_Descriptor *get_descriptor(lua_State *s, const char *spec)
+{
+	const LADSPA_Descriptor *dsc;
+	LADSPA_Descriptor_Function ldf;
+	char path[128];
+	char name[128];
+	void *lib;
+	int i = 0;
+
+	parse_spec(s,spec,path,name);
+
+	if ((dsc = lookup(dsc_cache,name)) != NULL)
+	{
+		return dsc;
+	}
+
+	lib = get_lib(s,path);
+	ldf = dlsym(lib,"ladspa_descriptor");
+
+	if (ldf == NULL)
+	{
+		luaL_error(s,"failed to load ladspa_descriptor from %s: %s",path,dlerror());
+	}
+
+	while ((dsc = ldf(i++)) != NULL)
+	{
+		if (strcmp(dsc->Name,name) == 0)
+		{
+			break;
+		}
+
+		if (strcmp(dsc->Label,name) == 0)
+		{
+			break;
+		}
+	}
+
+	if (dsc == NULL)
+	{
+		luaL_error(s,"ladspa plugin library %s does not define plugin %s",path,name);
+	}
+
+	cache(&dsc_cache,spec,(void*)dsc);
+
+	return dsc;
+}
+
+static void instantiate(struct ladspa *l, const ml_proc_args *args)
+{
+	unsigned long sr = ml_sample_rate();
+
+	l->hdl = l->dsc->instantiate(l->dsc,sr);
+
+	if (l->dsc->activate)
+	{
+		l->dsc->activate(l->hdl);
+	}
+
+	float *ptr;
+	size_t ii = 0, oi = 0, ci = 0;
+
+	for (size_t i = 0; i < l->dsc->PortCount; i++)
+	{
+		LADSPA_PortDescriptor pd = l->dsc->PortDescriptors[i];
+
+		if (LADSPA_IS_PORT_CONTROL(pd) && LADSPA_IS_PORT_INPUT(pd))
+		{
+			l->dsc->connect_port(l->hdl,i,&l->cntl[ci++]);
+			continue;
+		}
+
+		if (LADSPA_IS_PORT_AUDIO(pd) && LADSPA_IS_PORT_INPUT(pd))
+		{
+			ptr = args->in[ii++];
+			l->dsc->connect_port(l->hdl,i,ptr);
+			continue;
+		}
+
+		if (LADSPA_IS_PORT_AUDIO(pd) && LADSPA_IS_PORT_OUTPUT(pd))
+		{
+			ptr = args->out[oi++];
+			l->dsc->connect_port(l->hdl,i,ptr);
+			continue;
+		}
+	}
+}
+
+static void proc(const ml_proc_args *args)
+{
+	struct ladspa *l = args->userp;
+
+	if (l->hdl == NULL)
+	{
+		instantiate(l,args);
+	}
+
+	l->dsc->run(l->hdl,args->nframes);
+}
+
+static int l_load(lua_State *s)
+{
+	const char *spec = luaL_checkstring(s,1);
+	const LADSPA_Descriptor *dsc = get_descriptor(s,spec);
+
+	struct ladspa *l = calloc(1,sizeof(*l));
+	l->dsc = dsc;
+	l->node = ml_create_node(proc,l);
+	ml_label_node(l->node,"LADSPA (%s)",spec);
+
+	size_t num_cntl = 0, arg = 2;
+	for (size_t i = 0; i < dsc->PortCount; i++)
+	{
+		LADSPA_PortDescriptor pd = dsc->PortDescriptors[i];
+
+		if (LADSPA_IS_PORT_CONTROL(pd) && LADSPA_IS_PORT_INPUT(pd))
+		{
+			num_cntl++;
+		}
+
+		if (LADSPA_IS_PORT_AUDIO(pd) && LADSPA_IS_PORT_INPUT(pd))
+		{
+			ml_channel *src = mutil_get_channel(s,arg++);
+			ml_channel *dst = ml_add_input(l->node);
+			ml_connect(src,dst);
+		}
+
+		if (LADSPA_IS_PORT_AUDIO(pd) && LADSPA_IS_PORT_OUTPUT(pd))
+		{
+			ml_add_output(l->node);
+		}
+	}
+
+	l->cntl = calloc(1,sizeof(*l->cntl)*num_cntl);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = l;
+	luaL_setmetatable(s,LADSPA_TYPENAME);
+
+	return 1;
+}
+
+static int l_control(lua_State *s)
+{
+	struct ladspa *l = *(void**) luaL_checkudata(s,1,LADSPA_TYPENAME);
+	int i = luaL_checkinteger(s,2);
+	float v = luaL_checknumber(s,3);
+
+	if (i < 1 || i > l->dsc->PortCount)
+	{
+		luaL_error(s,"control port index out of bounds: %d",i);
+	}
+
+	if (!LADSPA_IS_PORT_CONTROL(l->dsc->PortDescriptors[i-1]))
+	{
+		luaL_error(s,"port %d is not a control port",i);
+	}
+
+	if (!LADSPA_IS_PORT_INPUT(l->dsc->PortDescriptors[i-1]))
+	{
+		luaL_error(s,"port %d is not an input port",i);
+	}
+
+	l->cntl[i-1] = v;
+	return 0;
+}
+
+static int l_info(lua_State *s)
+{
+	const char *spec = luaL_checkstring(s,1);
+	const LADSPA_Descriptor *dsc = get_descriptor(s,spec);
+
+	lua_newtable(s);
+	int info = lua_gettop(s);
+
+	lua_pushstring(s,dsc->Name);
+	lua_setfield(s,info,"name");
+
+	lua_pushstring(s,dsc->Label);
+	lua_setfield(s,info,"label");
+
+	lua_pushstring(s,dsc->Maker);
+	lua_setfield(s,info,"maker");
+
+	lua_pushstring(s,dsc->Copyright);
+	lua_setfield(s,info,"copyright");
+
+	lua_pushinteger(s,dsc->UniqueID);
+	lua_setfield(s,info,"id");
+
+	lua_newtable(s);
+	int ports = lua_gettop(s);
+
+	for (int i = 0; i < dsc->PortCount; i++)
+	{
+		const char *name = dsc->PortNames[i];
+		const LADSPA_PortDescriptor pd = dsc->PortDescriptors[i];
+		const LADSPA_PortRangeHint *prh = &dsc->PortRangeHints[i];
+		const LADSPA_PortRangeHintDescriptor prhd = prh->HintDescriptor;
+
+		const char *dir      = LADSPA_IS_PORT_INPUT(pd) ? "input" : "output";
+		const char *type     = LADSPA_IS_PORT_AUDIO(pd) ? "audio" : "control";
+		float lower          = prh->LowerBound;
+		float upper          = prh->UpperBound;
+		bool bounded_below   = LADSPA_IS_HINT_BOUNDED_BELOW(prhd);
+		bool bounded_above   = LADSPA_IS_HINT_BOUNDED_ABOVE(prhd);
+		bool toggled         = LADSPA_IS_HINT_TOGGLED(prhd);
+		bool sample_rate     = LADSPA_IS_HINT_SAMPLE_RATE(prhd);
+		bool logarithmic     = LADSPA_IS_HINT_LOGARITHMIC(prhd);
+		bool integer         = LADSPA_IS_HINT_INTEGER(prhd);
+		bool has_default     = LADSPA_IS_HINT_HAS_DEFAULT(prhd);
+		bool default_minimum = LADSPA_IS_HINT_DEFAULT_MINIMUM(prhd);
+		bool default_low     = LADSPA_IS_HINT_DEFAULT_LOW(prhd);
+		bool default_middle  = LADSPA_IS_HINT_DEFAULT_MIDDLE(prhd);
+		bool default_high    = LADSPA_IS_HINT_DEFAULT_HIGH(prhd);
+		bool default_maximum = LADSPA_IS_HINT_DEFAULT_MAXIMUM(prhd);
+		bool default_0       = LADSPA_IS_HINT_DEFAULT_0(prhd);
+		bool default_1       = LADSPA_IS_HINT_DEFAULT_1(prhd);
+		bool default_100     = LADSPA_IS_HINT_DEFAULT_100(prhd);
+		bool default_440     = LADSPA_IS_HINT_DEFAULT_440(prhd);
+
+		lua_newtable(s);
+		int port = lua_gettop(s);
+
+		lua_pushstring(s,name);
+		lua_setfield(s,port,"name");
+
+		lua_pushstring(s,dir);
+		lua_setfield(s,port,"direction");
+
+		lua_pushstring(s,type);
+		lua_setfield(s,port,"type");
+
+		lua_newtable(s);
+		int hints = lua_gettop(s);
+
+		// if (bounded_below) { lua_pushboolean(s,true); lua_setfield(s,hints,"bounded_below"); }
+		// if (bounded_above) { lua_pushboolean(s,true); lua_setfield(s,hints,"bounded_above"); }
+		if (toggled)       { lua_pushboolean(s,true); lua_setfield(s,hints,"toggled"); }
+		if (sample_rate)   { lua_pushboolean(s,true); lua_setfield(s,hints,"sample_rate"); }
+		if (logarithmic)   { lua_pushboolean(s,true); lua_setfield(s,hints,"logarithmic"); }
+		if (integer)       { lua_pushboolean(s,true); lua_setfield(s,hints,"integer"); }
+		if (bounded_below) { lua_pushnumber(s,lower); lua_setfield(s,hints,"lower_bound"); }
+		if (bounded_above) { lua_pushnumber(s,upper); lua_setfield(s,hints,"upper_bound"); }
+
+		if (has_default)
+		{
+			float def = 0;
+
+			if      (default_minimum) def = lower;
+			else if (default_low)     def = 0.25*lower + 0.75*upper;
+			else if (default_middle)  def = 0.5*lower + 0.5*upper;
+			else if (default_high)    def = 0.75*lower + 0.25*upper;
+			else if (default_maximum) def = upper;
+			else if (default_0)       def = 0;
+			else if (default_1)       def = 1;
+			else if (default_100)     def = 100;
+			else if (default_440)     def = 440;
+
+			lua_pushnumber(s,def);
+			lua_setfield(s,hints,"default");
+		}
+
+		lua_pushvalue(s,hints);
+		lua_setfield(s,port,"hints");
+
+		lua_pushvalue(s,port);
+		lua_rawseti(s,ports,i + 1);
+		lua_settop(s,ports);
+	}
+
+	lua_pushvalue(s,ports);
+	lua_setfield(s,info,"ports");
+
+	lua_settop(s,info);
+
+	return 1;
+}
+
+static int l_lib_info(lua_State *s)
+{
+	const char *path;
+	void *lib;
+	LADSPA_Descriptor_Function ldf;
+	const LADSPA_Descriptor *dsc;
+
+	path = luaL_checkstring(s,1);
+	lib= get_lib(s,path);
+	ldf = dlsym(lib,"ladspa_descriptor");
+
+	if (ldf == NULL)
+	{
+		luaL_error(s,"failed to load ladspa_descriptor from %s: %s",path,dlerror());
+	}
+
+	lua_newtable(s);
+	int info = lua_gettop(s);
+
+	int i = 0;
+	while ((dsc = ldf(i++)) != NULL)
+	{
+		lua_newtable(s);
+		int plugin = lua_gettop(s);
+
+		lua_pushstring(s,dsc->Name);
+		lua_setfield(s,plugin,"name");
+
+		lua_pushstring(s,dsc->Label);
+		lua_setfield(s,plugin,"label");
+
+		lua_pushstring(s,dsc->Maker);
+		lua_setfield(s,plugin,"maker");
+
+		lua_pushvalue(s,plugin);
+		lua_rawseti(s,info,i);
+		lua_settop(s,info);
+	}
+
+	lua_settop(s,info);
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct ladspa *l = *(void**) luaL_checkudata(s,1,LADSPA_TYPENAME);
+	size_t i = luaL_optinteger(s,2,1);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(l->node,i - 1);
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_ladspa(lua_State *s)
+{
+/*** LADSPA plugin support.
+
+	local mladspa = require 'melisma.ladspa'
+
+	local spec = 'caps.so:Plate'
+	local info = mladspa.info(spec)
+
+	print('name:',info.name)
+	print('maker:',info.maker)
+
+	local input = ...
+	local plate = mladspa.load(spec,input)
+
+	plate:control(1,1)
+
+	local left = plate:out(6)
+	local right = plate:out(7)
+
+@classmod ladspa
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Load a ladspa plugin.
+
+Input signals are connected to the plugins audio input ports in the
+order that they are declared.
+
+@static
+@function load
+@tparam string spec Plugin specification.
+@tparam channel ... Input signals.
+*/
+	lua_pushcfunction(s,l_load);
+	lua_setfield(s,tbl,"load");
+
+/*** Get information about a specific plugin.
+
+Plugin specifications are written in the format `<path>:<plugin>`,
+where `<path>` is the full name of the plugin library
+(e.g. `caps.so`), and `<plugin>` is the name or label of the plugin.
+If `<path>` is not an absolute path, the library is searched for
+first in the current directory, then in `LADSPA_PATH`.
+
+This can be used to generate more ergonomic plugin interfaces.
+
+@static
+@function info
+@tparam string spec Plugin specification.
+@treturn table Plugin information.
+*/
+	lua_pushcfunction(s,l_info);
+	lua_setfield(s,tbl,"info");
+
+/*** List plugins in the specified plugin library.
+
+If `path` is not an absolute path, the library is searched for
+first in the current directory, then in `LADSPA_PATH`.
+
+@static
+@function lib_info
+@tparam string path Path to plugin library.
+@treturn table List of short plugin descriptions.
+*/
+	lua_pushcfunction(s,l_lib_info);
+	lua_setfield(s,tbl,"lib_info");
+
+/*** Set the value of an input control port.
+
+Ports are indexed based on the order they are declared by the plugin.
+This also means the indices of control ports are not necessarily consecutive.
+
+@function control
+@tparam integer i One-based port index.
+@tparam number v New control port value.
+*/
+	lua_pushcfunction(s,l_control);
+	lua_setfield(s,tbl,"control");
+
+/*** Get the audio output port at the specified index.
+
+Ports are indexed based on the order they are declared by the plugin.
+This also means the indices of audio ports are not necessarily consecutive.
+
+@function out
+@tparam integer i One-based port index.
+@treturn channel Audio output at specified index.
+*/
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,"out");
+
+	luaL_newmetatable(s,LADSPA_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/lookback.c b/mod/lookback.c
new file mode 100644
index 0000000..115f823
--- /dev/null
+++ b/mod/lookback.c
@@ -0,0 +1,106 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+
+#include <lauxlib.h>
+
+#include "melisma.h"
+#include "mutil.h"
+
+#define LOOKBACK_TYPENAME "lookback"
+
+struct lookback
+{
+	ml_node *node;
+	size_t   cursor;
+	size_t   len;
+	float    buf[];
+};
+
+static void proc(const ml_proc_args *args)
+{
+	struct lookback *lb = args->userp;
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		args->out[0][i] = lb->buf[lb->cursor];
+		lb->buf[lb->cursor] = args->in[0][i];
+
+		lb->cursor++;
+
+		if (lb->cursor == lb->len)
+		{
+			lb->cursor = 0;
+		}
+	}
+}
+
+static int l_init(lua_State *s)
+{
+	float t = luaL_checknumber(s,1);
+	ml_channel *src = mutil_get_channel(s,2);
+
+	unsigned long sr = ml_sample_rate();
+	unsigned long len = sr*t;
+
+	struct lookback *lb = calloc(1,sizeof(*lb) + len*sizeof(lb->buf[0]));
+	lb->len = len;
+
+	ml_node *node = ml_create_node(proc,lb);
+	ml_label_node(node,"lookback");
+	lb->node = node;
+
+	ml_channel *dst = ml_add_input(node);
+	ml_connect(src,dst);
+	ml_add_output(node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = lb;
+	luaL_setmetatable(s,LOOKBACK_TYPENAME);
+
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct lookback *lb = *(void**) luaL_checkudata(s,1,LOOKBACK_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(lb->node,0);
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_lookback(lua_State *s)
+{
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,LOOKBACK_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/map.h b/mod/map.h
new file mode 100644
index 0000000..c56487e
--- /dev/null
+++ b/mod/map.h
@@ -0,0 +1,49 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef MAP_H
+#define MAP_H
+
+#include "melisma.h"
+#include <lauxlib.h>
+
+struct map
+{
+	float value;
+	int   channel;
+};
+
+static void map_from_arg(lua_State *s, struct map *m, int arg)
+{
+	if (lua_isnumber(s,arg))
+	{
+	}
+
+	if (lua_isuserdata(s,arg))
+	{
+	}
+
+	luaL_argerror(s,arg,"expected number or output channel");
+}
+
+static float map_get(struct map *m, size_t i, const ml_proc_args *args)
+{
+	return m->channel >= 0 ? args->in[m->channel][i] : m->value;
+}
+
+#endif
diff --git a/mod/mixer.c b/mod/mixer.c
new file mode 100644
index 0000000..ab5ade2
--- /dev/null
+++ b/mod/mixer.c
@@ -0,0 +1,114 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define MIXER_TYPENAME "mixer"
+
+static void proc(const ml_proc_args *args)
+{
+	float *out = args->out[0];
+
+	memset(out,0,args->nframes * sizeof(out[0]));
+
+	for (size_t i = 0; i < args->icnt; i++)
+	{
+		const float *in = args->in[i];
+
+		for (size_t j = 0; j < args->nframes; j++)
+		{
+			out[j] += in[j];
+		}
+	}
+}
+
+static int l_init(lua_State *s)
+{
+	int n = lua_gettop(s);
+
+	if (n == 0)
+	{
+		luaL_error(s,"need at least one input channel");
+	}
+
+	ml_node *node = ml_create_node(proc,NULL);
+	ml_label_node(node,"mix");
+
+	for (int i = 0; i < n; i++)
+	{
+		ml_channel *src = mutil_get_channel(s,i+1);
+		ml_channel *dst = ml_add_input(node);
+		ml_connect(src,dst);
+	}
+
+	ml_channel *out = ml_add_output(node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = out;
+	luaL_setmetatable(s,MIXER_TYPENAME);
+
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	ml_channel *c = *(void**) luaL_checkudata(s,1,MIXER_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = c;
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_mixer(lua_State *s)
+{
+	ml_check_version();
+
+/*** Mix signals.
+
+	local mmixer = require 'melisma.mixer'
+
+	local signals = ...
+	local mixer = mmixer.init(table.unpack(signals))
+
+@classmod mixer
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Mix input signals in to a single output signal.
+@static
+@function init
+@tparam channel ... Input signals.
+@treturn mixer The newly created mixer unit.
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,MIXER_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/mutil.h b/mod/mutil.h
new file mode 100644
index 0000000..215508b
--- /dev/null
+++ b/mod/mutil.h
@@ -0,0 +1,69 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef MUTIL_H
+#define MUTIL_H
+
+/* TODO: Move to main repo? */
+
+#include "melisma.h"
+#include <lauxlib.h>
+
+#define MUTIL_OUTPUT_CHANNEL_FUNCTION "__ml_out"
+
+static ml_channel *mutil_get_optchannel(lua_State *s, int i)
+{
+	ml_channel **c;
+
+	if ((c = luaL_testudata(s,i,MELISMA_OUTPUT_CHANNEL_TYPENAME)) != NULL)
+	{
+		return *c;
+	}
+
+	lua_getfield(s,i,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	if (!lua_isfunction(s,-1))
+	{
+		lua_pop(s,1);
+		return NULL;
+	}
+
+	lua_pushvalue(s,i);
+	lua_call(s,1,1);
+
+	if ((c = luaL_testudata(s,-1,MELISMA_OUTPUT_CHANNEL_TYPENAME)) != NULL)
+	{
+		lua_pop(s,1);
+		return *c;
+	}
+
+	lua_pop(s,1);
+	return NULL;
+}
+
+static ml_channel *mutil_get_channel(lua_State *s, int i)
+{
+	ml_channel *c = mutil_get_optchannel(s,i);
+	if (c == NULL)
+	{
+		luaL_argerror(s,i,"expected output channel");
+	}
+	return c;
+}
+
+#endif
diff --git a/mod/null.c b/mod/null.c
new file mode 100644
index 0000000..815d622
--- /dev/null
+++ b/mod/null.c
@@ -0,0 +1,76 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <string.h>
+#include <lua.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define NULL_TYPENAME "null"
+
+static void proc(const ml_proc_args *args)
+{
+	assert(args->ocnt == 1);
+	memset(args->out[0],0,sizeof(*args->out[0])*args->nframes);
+}
+
+static int l_init(lua_State *s)
+{
+	ml_node *node = ml_create_node(proc,NULL);
+	ml_label_node(node,"null");
+
+	(void) ml_add_output(node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = node;
+	luaL_setmetatable(s,NULL_TYPENAME);
+
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	ml_node *node = *(void**) luaL_checkudata(s,1,NULL_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(node,0);
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_null(lua_State *s)
+{
+	ml_check_version();
+
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,NULL_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/nullsink.c b/mod/nullsink.c
new file mode 100644
index 0000000..0cbd810
--- /dev/null
+++ b/mod/nullsink.c
@@ -0,0 +1,111 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <lua.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define NULLSINK_TYPENAME "nullsink"
+
+static int l_init(lua_State *s)
+{
+	ml_node *node = ml_create_node(NULL,NULL);
+	ml_label_node(node,"nullsink");
+	ml_node *root = ml_get_root_node();
+
+	ml_channel *src = ml_add_output(node);
+	ml_channel *dst = ml_add_input(root);
+
+	ml_connect(src,dst);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = node;
+	luaL_setmetatable(s,NULLSINK_TYPENAME);
+
+	return 1;
+}
+
+static int l_ref(lua_State *s)
+{
+	ml_node *node = *(void**) luaL_checkudata(s,1,NULLSINK_TYPENAME);
+	ml_channel *src = mutil_get_channel(s,2);
+	ml_channel *dst = ml_add_input(node);
+	ml_connect(src,dst);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = node;
+	luaL_setmetatable(s,NULLSINK_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_nullsink(lua_State *s)
+{
+	ml_check_version();
+
+/*** Reference otherwise disconnected nodes.
+
+	local mnullsink = require 'melisma.nullsink'
+	local minterp = require 'melisma.interp'
+	local mevent = require 'melisma.event'
+
+	local interp = minterp.init(0)
+	interp:linear(1,60)
+
+	-- The output of interp is disconnected.
+	-- Need to connect it to a nullsink so we
+	-- can sample it in the event callback below.
+	local nullsink = mnullsink.init()
+	nullsink:ref(interp)
+
+	mevent.schedule(30, function()
+		print('current value:', interp:sample())
+	end)
+
+@classmod nullsink
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Create a nullsink.
+@static
+@function init
+@treturn nullsink The newly created nullsink.
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+/*** Connect an input signal.
+
+This makes sure the input signal is processed
+even if it's not connected to anything else.
+
+@function ref
+@tparam channel input Input signal.
+@treturn nullsink
+*/
+	lua_pushcfunction(s,l_ref);
+	lua_setfield(s,tbl,"ref");
+
+	luaL_newmetatable(s,NULLSINK_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/oscil.c b/mod/oscil.c
new file mode 100644
index 0000000..7bc39c7
--- /dev/null
+++ b/mod/oscil.c
@@ -0,0 +1,438 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include <lua.h>
+#include <lauxlib.h>
+
+#include "melisma.h"
+#include "mutil.h"
+
+#define WAVETABLE_TYPENAME "wavetable"
+#define OSCIL_TYPENAME "oscil"
+
+#ifndef WAVETABLE_SIZE
+#define WAVETABLE_SIZE 2048
+#endif
+
+#define WAVETABLE_ALLOC_SIZE (sizeof(float)*WAVETABLE_SIZE)
+
+struct oscil
+{
+	ml_node       *node;
+	unsigned long  clk;
+	float          f;
+	float          a;
+	int            mf;
+	int            ma;
+	float          p;
+	float          v;
+	float          tbl[WAVETABLE_SIZE];
+};
+
+static float *push_new_wavetable(lua_State *s)
+{
+	float *ptr = lua_newuserdata(s,WAVETABLE_ALLOC_SIZE);
+	luaL_setmetatable(s,WAVETABLE_TYPENAME);
+	memset(ptr,0,WAVETABLE_ALLOC_SIZE);
+	return ptr;
+}
+
+static int l_const(lua_State *s)
+{
+	float v = luaL_checknumber(s,1);
+	float *tbl = push_new_wavetable(s);
+
+	for (size_t i = 0; i < WAVETABLE_SIZE; i++)
+	{
+		tbl[i] = v;
+	}
+
+	return 1;
+}
+
+static int l_sin(lua_State *s)
+{
+	float *tbl = push_new_wavetable(s);
+
+	for (size_t i = 0; i < WAVETABLE_SIZE; i++)
+	{
+		float f = 2.f * M_PI * (float) i / (float) WAVETABLE_SIZE;
+		tbl[i] = sinf(f);
+	}
+
+	return 1;
+}
+
+static int l_saw(lua_State *s)
+{
+	float *tbl = push_new_wavetable(s);
+
+	for (size_t i = 0; i < WAVETABLE_SIZE; i++)
+	{
+		tbl[i] =  2 * (float) i / (float) WAVETABLE_SIZE - 1;
+	}
+
+	return 1;
+}
+
+static int l_square(lua_State *s)
+{
+	float *tbl = push_new_wavetable(s);
+
+	for (size_t i = 0; i < WAVETABLE_SIZE; i++)
+	{
+		if (i >= WAVETABLE_SIZE/2)
+		{
+			tbl[i] = 1;
+		}
+		else
+		{
+			tbl[i] = -1;
+		}
+	}
+
+	return 1;
+}
+
+static int l_shift(lua_State *s)
+{
+	float *src = luaL_checkudata(s,1,WAVETABLE_TYPENAME);
+	float p = luaL_checknumber(s,2);
+
+	while (p < 0)
+	{
+		p += 2*M_PI;
+	}
+
+	while (p > 2*M_PI)
+	{
+		p -= 2*M_PI;
+	}
+
+	size_t offset = p/2.f/M_PI*WAVETABLE_SIZE;
+	float *dst = push_new_wavetable(s);
+
+	size_t i,d;
+	for (i=0, d=offset; i < WAVETABLE_SIZE; i++, d++)
+	{
+		dst[d % WAVETABLE_SIZE] = src[i];
+	}
+
+	return 1;
+}
+
+static int l_scale(lua_State *s)
+{
+	float *src = luaL_checkudata(s,1,WAVETABLE_TYPENAME);
+	int n = luaL_checkinteger(s,2);
+
+	// if (n <= 0 || (n & (n-1)) != 0)
+	// {
+	// 	luaL_error(s,"scaling factor must be a power of two");
+	// }
+
+	float *dst = push_new_wavetable(s);
+
+	for (size_t i = 0; i < WAVETABLE_SIZE; i++)
+	{
+		size_t j = (n*i) % WAVETABLE_SIZE;
+		dst[i] = src[j];
+	}
+
+	return 1;
+}
+
+static int l_add(lua_State *s)
+{
+	float *lhs = luaL_checkudata(s,1,WAVETABLE_TYPENAME);
+	float *rhs = luaL_checkudata(s,2,WAVETABLE_TYPENAME);
+	float *res = push_new_wavetable(s);
+
+	for (size_t i = 0; i < WAVETABLE_SIZE; i++)
+	{
+		res[i] = lhs[i] + rhs[i];
+	}
+
+	return 1;
+}
+
+static void proc(const ml_proc_args *args)
+{
+	struct oscil *oscil = args->userp;
+
+	unsigned long sr = ml_sample_rate();
+	float p = oscil->p;
+	float *dst = args->out[0];
+
+	float *mf = oscil->mf < 0 ? NULL : args->in[oscil->mf];
+	float *ma = oscil->ma < 0 ? NULL : args->in[oscil->ma];
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		float f = mf ? mf[i] : oscil->f;
+		float a = ma ? ma[i] : oscil->a;
+
+		float t = p*WAVETABLE_SIZE;
+
+		size_t i0 = (size_t) t;
+		size_t i1 = i0 + 1;
+
+		float ip = t - i0;
+
+		i0 &= (WAVETABLE_SIZE-1);
+		i1 &= (WAVETABLE_SIZE-1);
+
+		float s0 = oscil->tbl[i0];
+		float s1 = oscil->tbl[i1];
+
+		dst[i] = a*(s0 + ip*(s1 - s0));
+
+		p += f/sr;
+
+		if (p > 1)
+		{
+			p -= 1;
+		}
+	}
+
+	oscil->p = p;
+	oscil->v = dst[args->nframes-1];
+}
+
+static int l_init(lua_State *s)
+{
+	float *tbl = luaL_checkudata(s,1,WAVETABLE_TYPENAME);
+	float f = luaL_checknumber(s,2);
+	float a = luaL_checknumber(s,3);
+
+	struct oscil *oscil = calloc(1,sizeof(*oscil));
+	oscil->clk = 0;
+	oscil->f = f;
+	oscil->a = a;
+	oscil->mf = -1;
+	oscil->ma = -1;
+	oscil->p = 0;
+	oscil->v = a*tbl[0];
+
+	ml_node *node = ml_create_node(proc,oscil);
+	ml_label_node(node,"oscil");
+	ml_add_output(node);
+	oscil->node = node;
+
+	memcpy(oscil->tbl,tbl,WAVETABLE_ALLOC_SIZE);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = oscil;
+	luaL_setmetatable(s,OSCIL_TYPENAME);
+
+	return 1;
+}
+
+static int l_setf(lua_State *s)
+{
+	struct oscil *oscil = *(void**) luaL_checkudata(s,1,OSCIL_TYPENAME);
+	float v = luaL_checknumber(s,2);
+	oscil->f = v;
+	return 0;
+}
+
+static int l_seta(lua_State *s)
+{
+	struct oscil *oscil = *(void**) luaL_checkudata(s,1,OSCIL_TYPENAME);
+	float v = luaL_checknumber(s,2);
+	oscil->a = v;
+	return 0;
+}
+
+static int l_mapf(lua_State *s)
+{
+	struct oscil *oscil = *(void**) luaL_checkudata(s,1,OSCIL_TYPENAME);
+	ml_channel *src = mutil_get_channel(s,2);
+
+	oscil->mf = ml_num_inputs(oscil->node);
+
+	ml_channel *dst = ml_add_input(oscil->node);
+	ml_connect(src,dst);
+
+	return 0;
+}
+
+static int l_mapa(lua_State *s)
+{
+	struct oscil *oscil = *(void**) luaL_checkudata(s,1,OSCIL_TYPENAME);
+	ml_channel *src = mutil_get_channel(s,2);
+
+	oscil->ma = ml_num_inputs(oscil->node);
+
+	ml_channel *dst = ml_add_input(oscil->node);
+	ml_connect(src,dst);
+
+	return 0;
+}
+
+static int l_sample(lua_State *s)
+{
+	struct oscil *oscil = *(void**) luaL_checkudata(s,1,OSCIL_TYPENAME);
+	lua_pushnumber(s,oscil->v);
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct oscil *oscil = *(void**) luaL_checkudata(s,1,OSCIL_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(oscil->node,0);
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_oscil(lua_State *s)
+{
+
+/*** Wavetable backed oscillators.
+
+	local moscil = require 'melisma.oscil'
+	local mexpression = require 'melisma.expression'
+
+	local wt = moscil.wavetable.sin()
+
+	-- Make an LFO for controlling the frequency.
+	local lfo_oscil = moscil.init(wt,1,1)
+
+	-- Map [-1, 1] to [440, 880]
+	local lfo = (440 + (1 + mexpression.input(lfo_oscil,0) / 2) * 440):build()
+
+	local oscil = moscil.init(wt,0,0.5)
+	oscil:mapf(lfo)
+
+@classmod oscil
+*/
+	lua_newtable(s);
+	int tbl = lua_absindex(s,lua_gettop(s));
+
+/*** Initialize an oscillator.
+@static
+@function init
+@tparam wavetable wt
+@tparam number freq
+@tparam number amp
+@treturn oscil
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+/*** Set oscillator frequency.
+@function setf
+@tparam number freq
+*/
+	lua_pushcfunction(s,l_setf);
+	lua_setfield(s,tbl,"setf");
+
+/*** Set oscillator amplitude.
+@function seta
+@tparam number amp
+*/
+	lua_pushcfunction(s,l_seta);
+	lua_setfield(s,tbl,"seta");
+
+/*** Map a signal to the frequency.
+@function mapf
+@tparam channel sig
+*/
+	lua_pushcfunction(s,l_mapf);
+	lua_setfield(s,tbl,"mapf");
+
+/*** Map a signal to the amplitude.
+@function mapa
+@tparam channel sig
+*/
+	lua_pushcfunction(s,l_mapa);
+	lua_setfield(s,tbl,"mapa");
+
+/*** Get the current oscillator value.
+@function sample
+@treturn number
+*/
+	lua_pushcfunction(s,l_sample);
+	lua_setfield(s,tbl,"sample");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,OSCIL_TYPENAME);
+	int oscil_mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,oscil_mt,"__index");
+
+/***
+@type wavetable
+*/
+	lua_newtable(s);
+	int wt_tbl = lua_absindex(s,lua_gettop(s));
+
+	lua_pushvalue(s,wt_tbl);
+	lua_setfield(s,tbl,"wavetable");
+
+	lua_pushcfunction(s,l_const);
+	lua_setfield(s,wt_tbl,"const");
+
+/*** Sine wave.
+@static
+@function wavetable.sin
+@treturn wavetable
+*/
+	lua_pushcfunction(s,l_sin);
+	lua_setfield(s,wt_tbl,"sin");
+
+/*** Saw wave.
+@static
+@function wavetable.saw
+@treturn wavetable
+*/
+	lua_pushcfunction(s,l_saw);
+	lua_setfield(s,wt_tbl,"saw");
+
+/*** Square wave.
+@static
+@function wavetable.square
+@treturn wavetable
+*/
+	lua_pushcfunction(s,l_square);
+	lua_setfield(s,wt_tbl,"square");
+
+	lua_pushcfunction(s,l_shift);
+	lua_setfield(s,wt_tbl,"shift");
+
+	lua_pushcfunction(s,l_scale);
+	lua_setfield(s,wt_tbl,"scale");
+
+	luaL_newmetatable(s,WAVETABLE_TYPENAME);
+	int wt_mt = lua_gettop(s);
+
+	lua_pushvalue(s,wt_tbl);
+	lua_setfield(s,wt_mt,"__index");
+
+	lua_pushcfunction(s,l_add);
+	lua_setfield(s,wt_mt,"__add");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/pan.c b/mod/pan.c
new file mode 100644
index 0000000..84a0551
--- /dev/null
+++ b/mod/pan.c
@@ -0,0 +1,187 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define PAN_TYPENAME "pan"
+
+struct pan
+{
+	ml_channel *l_out;
+	ml_channel *r_out;
+	float       val;
+	bool        map;
+};
+
+static void proc(const ml_proc_args *args)
+{
+	struct pan *pan = args->userp;
+
+	float val,*in,*l_out,*r_out,*map;
+	in = args->in[0];
+	l_out = args->out[0];
+	r_out = args->out[1];
+	map = pan->map ? args->in[1] : NULL;
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		val = map ? map[i] : pan->val;
+		l_out[i] = val*in[i];
+		r_out[i] = (1 - val)*in[i];
+	}
+}
+
+static int l_init(lua_State *s)
+{
+	ml_channel *dst,*src,*map_dst,*map_src = NULL;
+	float val = 0;
+
+	if (lua_isuserdata(s,1))
+	{
+		map_src = mutil_get_channel(s,1);
+	}
+	else
+	{
+		val = luaL_checknumber(s,1);
+	}
+
+	src = mutil_get_channel(s,2);
+
+	struct pan *pan = calloc(1,sizeof(*pan));
+	pan->val = val;
+	pan->map = map_src != NULL;
+
+	ml_node *node = ml_create_node(proc,pan);
+	ml_label_node(node,"pan");
+
+	dst = ml_add_input(node);
+	pan->l_out = ml_add_output(node);
+	pan->r_out = ml_add_output(node);
+
+	ml_connect(src,dst);
+
+	if (pan->map)
+	{
+		map_dst = ml_add_input(node);
+		ml_connect(map_src,map_dst);
+	}
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = pan;
+	luaL_setmetatable(s,PAN_TYPENAME);
+
+	return 1;
+}
+
+static int l_left(lua_State *s)
+{
+	struct pan *pan = *(void**) luaL_checkudata(s,1,PAN_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = pan->l_out;
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+static int l_right(lua_State *s)
+{
+	struct pan *pan = *(void**) luaL_checkudata(s,1,PAN_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = pan->r_out;
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+static int l_set(lua_State *s)
+{
+	struct pan *pan = *(void**) luaL_checkudata(s,1,PAN_TYPENAME);
+	pan->val = luaL_checknumber(s,2);
+	return 0;
+}
+
+int luaopen_melisma_pan(lua_State *s)
+{
+	ml_check_version();
+
+/*** Panning
+
+	local mpan = require 'melisma.pan'
+	local mexpression = require 'melisma.expression'
+	local moscil = require 'melisma.oscil'
+
+	local wt = moscil.wavetable.sin()
+	local lfo_oscil = moscil.init(wt,1,1)
+	local lfo = (1 + mexpression.input(lfo_oscil,0) / 2):build()
+
+	local oscil = moscil.init(wt,440,0.5)
+	local pan = mpan.init(lfo,oscil)
+
+	local left = pan:left()
+	local right = pan:right()
+
+@classmod pan
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Initialize a panning unit.
+
+A panning value ranges from 0 to 1, where a value of 0
+will pan everything to the left.
+
+@static
+@function init
+@tparam number|channel x Constant pan or a controlling signal.
+@tparam channel sig Input signal.
+@treturn pan The newly created panning unit.
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+/*** Get the left output signal.
+@function left
+@treturn channel
+*/
+	lua_pushcfunction(s,l_left);
+	lua_setfield(s,tbl,"left");
+
+
+/*** Get the right output signal.
+@function right
+@treturn channel
+*/
+	lua_pushcfunction(s,l_right);
+	lua_setfield(s,tbl,"right");
+
+/*** Set the panning value.
+@function set
+@tparam number x
+*/
+	lua_pushcfunction(s,l_set);
+	lua_setfield(s,tbl,"set");
+
+	luaL_newmetatable(s,PAN_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/passthrough.c b/mod/passthrough.c
new file mode 100644
index 0000000..775c6fe
--- /dev/null
+++ b/mod/passthrough.c
@@ -0,0 +1,82 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <string.h>
+#include <lua.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+
+#define PASSTHROUGH_TYPENAME "passthrough"
+
+static void proc(const ml_proc_args *args)
+{
+	assert(args->icnt == 1);
+	assert(args->ocnt == 1);
+	memcpy(args->out[0],args->in[0],args->nframes*sizeof(float));
+}
+
+static int l_init(lua_State *s)
+{
+	ml_channel *src = mutil_get_channel(s,1);
+
+	ml_node *node = ml_create_node(proc,NULL);
+	ml_label_node(node,"passthrough");
+
+	ml_channel *dst = ml_add_input(node);
+	ml_connect(src,dst);
+
+	(void) ml_add_output(node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = node;
+	luaL_setmetatable(s,PASSTHROUGH_TYPENAME);
+
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	ml_node *node = *(void**) luaL_checkudata(s,1,PASSTHROUGH_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(node,0);
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_passthrough(lua_State *s)
+{
+	ml_check_version();
+
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,PASSTHROUGH_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/playback.c b/mod/playback.c
new file mode 100644
index 0000000..f9d22ca
--- /dev/null
+++ b/mod/playback.c
@@ -0,0 +1,342 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "mutil.h"
+#include "sample.h"
+
+#define PLAYBACK_TYPENAME "playback"
+
+struct playback
+{
+	ml_node       *node;
+	struct sample *smp;
+	double         speed;
+	double         phase;
+	bool           active;
+	bool           loop;
+	int            fn;
+	int            arg;
+};
+
+static void proc(const ml_proc_args *args)
+{
+	struct playback *pb = args->userp;
+
+	if (pb->smp == NULL)
+	{
+		memset(args->out[0],0,sizeof(*args->out[0])*args->nframes);
+		return;
+	}
+
+	unsigned long sr = ml_sample_rate();
+	double phase = pb->phase;
+	float *dst = args->out[0];
+	size_t len = pb->smp->len;
+	float *data = pb->smp->data;
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		if (!pb->active)
+		{
+			memset(&dst[i],0,(args->nframes - i)*sizeof(*dst));
+			return;
+		}
+
+		float t = phase*len;
+
+		size_t i0 = (size_t) t;
+		size_t i1 = i0 + 1;
+		float ip = t - i0;
+
+		i0 %= len;
+		i1 %= len;
+
+		float s0 = data[i0];
+		float s1 = data[i1];
+
+		dst[i] = s0 + ip*(s1 - s0);
+
+		phase += pb->speed/len;
+
+		while (phase > 1)
+		{
+			phase -= 1;
+
+			if (pb->fn != LUA_NOREF)
+			{
+				ml_schedule_event(0,pb->fn,pb->arg);
+
+			}
+
+			if (!pb->loop)
+			{
+				pb->active = false;
+				pb->phase = 0;
+			}
+		}
+
+		while (phase < 0)
+		{
+			phase += 1;
+
+			if (pb->fn != LUA_NOREF)
+			{
+				ml_schedule_event(0,pb->fn,pb->arg);
+
+			}
+
+			if (!pb->loop)
+			{
+				pb->active = false;
+				pb->phase = 0;
+			}
+		}
+	}
+
+	pb->phase = phase;
+}
+
+static int l_init(lua_State *s)
+{
+	struct sample *smp = NULL;
+
+	if (!lua_isnoneornil(s,1))
+	{
+		smp = *(void**) luaL_checkudata(s,1,SAMPLE_TYPENAME);
+	}
+
+	struct playback *pb = calloc(1,sizeof(*pb));
+
+	pb->smp = smp;
+	pb->speed = 1;
+	pb->fn = LUA_NOREF;
+	pb->arg = LUA_NOREF;
+	pb->node = ml_create_node(proc,pb);
+	ml_label_node(pb->node,"playback (%s)",smp ? smp->path : "NULL");
+
+	ml_add_output(pb->node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = pb;
+	luaL_setmetatable(s,PLAYBACK_TYPENAME);
+
+	return 1;
+}
+
+static int l_set_sample(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	struct sample *smp = *(void**) luaL_checkudata(s,2,SAMPLE_TYPENAME);
+	pb->smp = smp;
+	return 0;
+}
+
+static int l_play(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	pb->active = true;
+	return 0;
+}
+
+static int l_pause(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	pb->active = false;
+	return 0;
+}
+
+static int l_reset(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	pb->phase = 0;
+	return 0;
+}
+
+static int l_stop(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	pb->phase = 0;
+	pb->active = false;
+	return 0;
+}
+
+static int l_speed(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+
+	if (!lua_isnil(s,2))
+	{
+		pb->speed = luaL_checknumber(s,2);
+	}
+
+	lua_pushnumber(s,pb->speed);
+	return 1;
+}
+
+static int l_loop(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+
+	if (!lua_isnil(s,2))
+	{
+		luaL_checktype(s,2,LUA_TBOOLEAN);
+		pb->loop = lua_toboolean(s,2);
+	}
+
+	lua_pushboolean(s,pb->loop);
+	return 1;
+}
+
+static int l_phase(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+
+	if (!lua_isnil(s,2))
+	{
+		double phase = luaL_checknumber(s,2);
+
+		if (phase > 1)
+		{
+			phase = 1;
+		}
+
+		if (phase < 0)
+		{
+			phase = 0;
+		}
+
+		pb->phase = phase;
+	}
+
+	lua_pushnumber(s,pb->phase);
+	return 1;
+}
+
+static int l_out(lua_State *s)
+{
+	struct playback *pb = *(void**) luaL_checkudata(s,1,PLAYBACK_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(pb->node,0);
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+int luaopen_melisma_playback(lua_State *s)
+{
+/*** Audio sample playback.
+
+	local msample = require 'melisma.sample'
+	local mplayback = require 'melisma.playback'
+
+	local sample = msample.load('sample.wav')
+	local playb = mplayback.init(sample)
+
+	playb:loop(true)
+	playb:spped(2)
+	playb:play()
+
+@classmod playback
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Intialize a playback unit.
+@static
+@function init
+@tparam sample|nil smp
+@treturn playback
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+/*** Set playback sample.
+@function set_sample
+@tparam sample smp
+*/
+	lua_pushcfunction(s,l_set_sample);
+	lua_setfield(s,tbl,"set_sample");
+
+/*** Start playback.
+@function play
+*/
+	lua_pushcfunction(s,l_play);
+	lua_setfield(s,tbl,"play");
+
+/*** Pause playback.
+@function pause
+*/
+	lua_pushcfunction(s,l_pause);
+	lua_setfield(s,tbl,"pause");
+
+/*** Stop playback.
+
+Equivalent to @{playback.pause}; @{playback.reset}.
+
+@function stop
+*/
+	lua_pushcfunction(s,l_stop);
+	lua_setfield(s,tbl,"stop");
+
+
+/*** Reset playback.
+
+Equivalent to @{playback.phase}(0).
+
+@function reset
+*/
+	lua_pushcfunction(s,l_reset);
+	lua_setfield(s,tbl,"reset");
+
+/*** Set playback speed.
+
+A negative speed will play the sample in reverse.
+
+@function reset
+*/
+	lua_pushcfunction(s,l_speed);
+	lua_setfield(s,tbl,"speed");
+
+/*** Enable/disable automatic looping.
+@function loop
+@tparam bool b
+*/
+	lua_pushcfunction(s,l_loop);
+	lua_setfield(s,tbl,"loop");
+
+/*** Set playback phase.
+@function phase
+@tparam number x Phase ranging from 0 to 1.
+*/
+	lua_pushcfunction(s,l_phase);
+	lua_setfield(s,tbl,"phase");
+
+	lua_pushcfunction(s,l_out);
+	lua_setfield(s,tbl,MUTIL_OUTPUT_CHANNEL_FUNCTION);
+
+	luaL_newmetatable(s,PLAYBACK_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/sample.c b/mod/sample.c
new file mode 100644
index 0000000..6a3a24b
--- /dev/null
+++ b/mod/sample.c
@@ -0,0 +1,180 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <lauxlib.h>
+#include <sndfile.h>
+#include <samplerate.h>
+#include "melisma.h"
+#include "sample.h"
+
+static struct sample *alloc_sample(size_t len)
+{
+	struct sample *s = malloc(sizeof(*s) + len*sizeof(s->data[0]));
+	s->len = len;
+	return s;
+}
+
+static struct sample *resample(struct sample *old, unsigned long from, unsigned long to)
+{
+	double ratio = (double)to / (double)from;
+	size_t new_len = ratio * old->len;
+	struct sample *new = alloc_sample(new_len);
+
+	SRC_DATA src_data = {
+		.data_in = old->data,
+		.data_out = new->data,
+		.input_frames = old->len,
+		.output_frames = new->len,
+		.src_ratio = ratio,
+	};
+
+	src_simple(&src_data,SRC_SINC_MEDIUM_QUALITY,1);
+
+	new->path = old->path;
+	free(old);
+
+	return new;
+}
+
+static int l_load(lua_State *s)
+{
+	const char *path = luaL_checkstring(s,1);
+
+	SF_INFO info;
+	SNDFILE *f;
+
+	f = sf_open(path,SFM_READ,&info);
+
+	if (f == NULL)
+	{
+		luaL_error(s,"failed to open audio file '%s': %s",path,sf_strerror(f));
+	}
+
+	size_t len = info.frames*info.channels;
+	float *data = malloc(sizeof(*data)*len);
+
+	size_t off = 0;
+	while (off < len)
+	{
+		ssize_t res = sf_read_float(f,&data[off],len - off);
+
+		if (res < 0)
+		{
+			luaL_error(s,"failed to open audio file '%s': %s",path,sf_strerror(f));
+		}
+
+		off += res;
+	}
+
+	sf_close(f);
+
+	size_t samplerate = ml_sample_rate();
+
+	for (size_t c = 0; c < info.channels; c++)
+	{
+		struct sample *smp = alloc_sample(info.frames);
+		smp->path = strdup(path);
+
+		for (size_t i = 0; i < info.frames; i++)
+		{
+			smp->data[i] = data[i*info.channels + c];
+		}
+
+		if (info.samplerate != samplerate)
+		{
+			smp = resample(smp,info.samplerate,samplerate);
+		}
+
+		*(void**) lua_newuserdata(s,sizeof(void*)) = smp;
+		luaL_setmetatable(s,SAMPLE_TYPENAME);
+	}
+
+	free(data);
+
+	return info.channels;
+}
+
+static int l_length(lua_State *s)
+{
+	struct sample *smp = *(void**) luaL_checkudata(s,1,SAMPLE_TYPENAME);
+	unsigned long sr = ml_sample_rate();
+	double l = smp->len / (double)sr;
+	lua_pushnumber(s,l);
+	return 1;
+}
+
+static int l_path(lua_State *s)
+{
+	struct sample *smp = *(void**) luaL_checkudata(s,1,SAMPLE_TYPENAME);
+	lua_pushstring(s,smp->path);
+	return 1;
+}
+
+int luaopen_melisma_sample(lua_State *s)
+{
+/*** Load audio samples.
+
+	local msample = require 'melisma.sample'
+
+	local smp = msample.load('sample.wav')
+
+	print(smp:length())
+	print(smp:path())
+
+@classmod sample
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Load an audio sample.
+
+If necessary, the audio will be resampled to the current sample rate.
+
+@static
+@function load
+@tparam string path
+@treturn sample
+*/
+	lua_pushcfunction(s,l_load);
+	lua_setfield(s,tbl,"load");
+
+/*** Get sample length.
+@function length
+@treturn number The length of the sample in seconds.
+*/
+	lua_pushcfunction(s,l_length);
+	lua_setfield(s,tbl,"length");
+
+/*** Get sample path.
+@function path
+@treturn string The path that the sample was loaded from.
+*/
+	lua_pushcfunction(s,l_path);
+	lua_setfield(s,tbl,"path");
+
+	luaL_newmetatable(s,SAMPLE_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/sample.h b/mod/sample.h
new file mode 100644
index 0000000..af2ec83
--- /dev/null
+++ b/mod/sample.h
@@ -0,0 +1,33 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef SAMPLE_H_INCLUDED
+#define SAMPLE_H_INCLUDED
+
+#include <stddef.h>
+
+#define SAMPLE_TYPENAME "audio sample"
+
+struct sample
+{
+	char   *path;
+	size_t  len;
+	float   data[];
+};
+
+#endif
diff --git a/mod/serial.c b/mod/serial.c
new file mode 100644
index 0000000..a7b51db
--- /dev/null
+++ b/mod/serial.c
@@ -0,0 +1,511 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <ctype.h>
+#include <unistd.h>
+#include <termios.h>
+#include <fcntl.h>
+#include <lauxlib.h>
+#include "melisma.h"
+#include "melisma/ring.h"
+
+#define SERIAL_TYPENAME  "serial"
+#define DEFAULT_BAUD     9600
+#define DEFAULT_FORMAT   "8N1"
+#define DEFAULT_ENCODING "cstring"
+#define DEFAULT_BUFSIZE  4096
+
+struct serial;
+
+typedef int (*decode_fn)(struct serial*);
+
+struct conf
+{
+	char       *path;
+	char       *format;
+	int         datasize;
+	int         stopbits;
+	int         parity;
+	int         baud;
+	int         baudflag;
+	decode_fn   decode;
+	int         bufsize;
+	int         callb;
+};
+
+struct serial
+{
+	struct conf   conf;
+	int           fd;
+	int           synced;
+	size_t        len;
+	size_t        cap;
+	uint8_t      *data;
+	uint8_t      *tmpdata;
+	ml_ring      *ring;
+	lua_State    *state;
+};
+
+static int cstring(struct serial*);
+
+static const struct {
+	decode_fn   decode;
+	const char *name;
+} encoding_map[] = {
+	{ cstring, "cstring" },
+	{ NULL,    NULL },
+};
+
+static void free_conf(struct conf *c)
+{
+	free(c->path);
+	free(c->format);
+}
+
+static void put_byte(struct serial *se, int c)
+{
+	if (se->len == se->cap)
+	{
+		se->cap = se->cap == 0 ? 32 : se->cap*2;
+		se->data = realloc(se->data,se->cap);
+		se->tmpdata = realloc(se->tmpdata,se->cap);
+	}
+	se->data[se->len++] = c;
+}
+
+static void io_handler(int fd, int events, void *args)
+{
+	struct serial *se = args;
+	if (se->conf.decode(se) == 0)
+	{
+		if (ml_ring_has_space(se->ring,se->len + sizeof se->len))
+		{
+			ml_ring_write_blocking(se->ring,&se->len,sizeof se->len);
+			ml_ring_write_blocking(se->ring,se->data,se->len);
+		}
+		else
+		{
+			fprintf(stderr,"dropped %lu bytes\n",se->len);
+		}
+	}
+	else
+	{
+		fprintf(stderr,"failed to decode message\n");
+	}
+	se->len = 0;
+}
+
+static void read_conf(lua_State *s, int tbl, struct conf *c)
+{
+	int top = lua_gettop(s);
+	lua_getfield(s,tbl,"path");
+
+	if (lua_isnil(s,-1))
+	{
+		free_conf(c);
+		luaL_error(s,"missing 'path' field");
+	}
+
+	if (!lua_isstring(s,-1))
+	{
+		free_conf(c);
+		luaL_error(s,"'path' field is not a string");
+	}
+
+	c->path = strdup(lua_tostring(s,-1));
+	lua_settop(s,top);
+
+
+	lua_getfield(s,tbl,"baud");
+
+	if (lua_isnil(s,-1))
+	{
+		c->baud = DEFAULT_BAUD;
+	}
+	else if (lua_isinteger(s,-1))
+	{
+		c->baud = lua_tointeger(s,-1);
+	}
+	else
+	{
+		free_conf(c);
+		luaL_error(s,"'baud' field is not an integer");
+	}
+
+	switch (c->baud)
+	{
+	case 0:       c->baudflag = B0;       break;
+	case 50:      c->baudflag = B50;      break;
+	case 75:      c->baudflag = B75;      break;
+	case 110:     c->baudflag = B110;     break;
+	case 134:     c->baudflag = B134;     break;
+	case 150:     c->baudflag = B150;     break;
+	case 200:     c->baudflag = B200;     break;
+	case 300:     c->baudflag = B300;     break;
+	case 600:     c->baudflag = B600;     break;
+	case 1200:    c->baudflag = B1200;    break;
+	case 1800:    c->baudflag = B1800;    break;
+	case 2400:    c->baudflag = B2400;    break;
+	case 4800:    c->baudflag = B4800;    break;
+	case 9600:    c->baudflag = B9600;    break;
+	case 19200:   c->baudflag = B19200;   break;
+	case 38400:   c->baudflag = B38400;   break;
+	case 57600:   c->baudflag = B57600;   break;
+	case 115200:  c->baudflag = B115200;  break;
+	case 230400:  c->baudflag = B230400;  break;
+	case 460800:  c->baudflag = B460800;  break;
+	case 500000:  c->baudflag = B500000;  break;
+	case 576000:  c->baudflag = B576000;  break;
+	case 921600:  c->baudflag = B921600;  break;
+	case 1000000: c->baudflag = B1000000; break;
+	case 1152000: c->baudflag = B1152000; break;
+	case 1500000: c->baudflag = B1500000; break;
+	case 2000000: c->baudflag = B2000000; break;
+	default:      c->baudflag = -1;       break;
+	}
+
+	if (c->baudflag < 0)
+	{
+		free_conf(c);
+		luaL_error(s,"unsupported baud rate %d",c->baud);
+	}
+
+	lua_settop(s,top);
+
+	const char *format;
+	lua_getfield(s,tbl,"format");
+
+	if (lua_isnil(s,-1))
+	{
+		format = DEFAULT_FORMAT;
+	}
+	else if (lua_isstring(s,-1))
+	{
+		format = lua_tostring(s,-1);
+	}
+	else
+	{
+		free_conf(c);
+		luaL_error(s,"'format' field is not a string");
+	}
+
+	c->format = strdup(format);
+
+	if (strlen(format) != 3 ||
+	    !strchr("5678",format[0]) ||
+	    !strchr("NEOneo",format[1]) ||
+	    !strchr("12",format[2]))
+	{
+		free_conf(c);
+		luaL_error(s,"invalid frame format '%s'",format);
+	}
+
+	c->datasize = format[0] - '0';
+	c->parity = toupper(format[1]);
+	c->stopbits = format[2] - '0';
+
+	lua_settop(s,top);
+
+	lua_getfield(s,tbl,"encoding");
+	const char *encoding = NULL;
+
+	if (lua_isnil(s,-1))
+	{
+		encoding = DEFAULT_ENCODING;
+	}
+	else if (lua_isstring(s,-1))
+	{
+		encoding = lua_tostring(s,-1);
+	}
+	else
+	{
+		free_conf(c);
+		luaL_error(s,"'encoding' field is not a string");
+	}
+
+	for (size_t i = 0;; i++)
+	{
+		c->decode = encoding_map[i].decode;
+		const char *name = encoding_map[i].name;
+
+		if (c->decode == NULL)
+		{
+			free_conf(c);
+			luaL_error(s,"unknown encoding '%s'",encoding);
+		}
+
+		if (strcmp(name,encoding) == 0)
+		{
+			break;
+		}
+	}
+
+	lua_getfield(s,tbl,"bufsize");
+
+	if (lua_isnil(s,-1))
+	{
+		c->bufsize = DEFAULT_BUFSIZE;
+	}
+	else if (lua_isinteger(s,-1))
+	{
+		c->bufsize = lua_tointeger(s,-1);
+
+		if (c->bufsize <= 0)
+		{
+			luaL_error(s,"invalid bufsize %d",c->bufsize);
+		}
+	}
+	else
+	{
+		free_conf(c);
+		luaL_error(s,"'bufsize' is not an integer");
+	}
+
+	lua_getfield(s,tbl,"callback");
+
+	if (lua_isnil(s,-1))
+	{
+		c->callb = LUA_NOREF;
+	}
+	else if (lua_isfunction(s,-1))
+	{
+		c->callb = luaL_ref(s,LUA_REGISTRYINDEX);
+	}
+	else
+	{
+		free_conf(c);
+		luaL_error(s,"'callback' is not a function");
+	}
+}
+
+static void setup_tty(struct termios *t, struct conf *c)
+{
+	cfsetispeed(t,c->baudflag);
+
+	switch (c->stopbits)
+	{
+	case 1: t->c_cflag &= ~CSTOPB; break;
+	case 2: t->c_cflag |= CSTOPB; break;
+	default: assert(0);
+	}
+
+	switch (c->parity)
+	{
+	case 'N':
+	case 'n':
+		t->c_cflag &= ~PARENB;
+		break;
+	case 'O':
+	case 'o':
+		t->c_cflag |= PARENB;
+		t->c_cflag |= PARODD;
+		break;
+	case 'E':
+	case 'e':
+		t->c_cflag |= PARENB;
+		t->c_cflag &= ~PARODD;
+		break;
+	default:
+		assert(0);
+	}
+
+	t->c_cflag &= ~CSIZE;
+
+	switch (c->datasize)
+	{
+	case 5: t->c_cflag |= CS5; break;
+	case 6: t->c_cflag |= CS6; break;
+	case 7: t->c_cflag |= CS7; break;
+	case 8: t->c_cflag |= CS8; break;
+	default: assert(0);
+	}
+
+	t->c_cflag |= CREAD|CLOCAL;
+	t->c_cflag &= ~CRTSCTS;
+	t->c_lflag &= ~(ICANON|ECHO|ISIG);
+	t->c_iflag &= ~(IXON|IXOFF|IXANY);
+	t->c_oflag &= ~OPOST;
+	t->c_cc[VMIN] = 1;
+	t->c_cc[VTIME] = 0;
+}
+
+static void proc(const ml_proc_args *args)
+{
+	struct serial *se = args->userp;
+	size_t len;
+
+	while (ml_ring_read(se->ring,&len,sizeof len) == sizeof len)
+	{
+		ml_ring_read_blocking(se->ring,se->tmpdata,len);
+
+		if (se->conf.callb != LUA_NOREF)
+		{
+			lua_pushlstring(se->state,(const char*)se->tmpdata,len);
+			int arg = luaL_ref(se->state,LUA_REGISTRYINDEX);
+			ml_schedule_event(0,se->conf.callb,arg);
+		}
+	}
+}
+
+static int l_open(lua_State *s)
+{
+	luaL_checktype(s,1,LUA_TTABLE);
+
+	struct conf conf = {0};
+
+	read_conf(s,1,&conf);
+
+	int fd = open(conf.path,O_RDONLY|O_NOCTTY);
+
+	if (fd < 0)
+	{
+		luaL_error(s,"failed to open %s: %s",conf.path,strerror(errno));
+	}
+
+	struct termios tty = {0};
+	tcgetattr(fd,&tty);
+
+	setup_tty(&tty,&conf);
+
+	tcsetattr(fd,TCSANOW,&tty);
+	tcflush(fd,TCIFLUSH);
+
+	struct serial *se = calloc(1,sizeof(*se));
+	se->fd = fd;
+	se->conf = conf;
+	se->ring = ml_ring_init(conf.bufsize);
+	se->state = s;
+
+	*(void**) lua_newuserdata(s,sizeof(void**)) = se;
+	luaL_setmetatable(s,SERIAL_TYPENAME);
+
+	ml_add_io_handler(fd,POLLIN,io_handler,se);
+
+	ml_node *node = ml_create_node(proc,se);
+	ml_channel *src = ml_add_output(node);
+	ml_channel *dst = ml_add_input(ml_get_root_node());
+	ml_connect(src,dst);
+	ml_label_node(node,"serial %s",conf.path);
+
+	return 1;
+}
+
+static int read_byte(struct serial *se)
+{
+	uint8_t c;
+
+	if (read(se->fd,&c,sizeof c) < sizeof c)
+	{
+		return -1;
+	}
+
+	return c;
+}
+
+static int sync_(struct serial *se)
+{
+	int c;
+
+	if (se->synced)
+	{
+		return 0;
+	}
+
+	while ((c = read_byte(se)) != 0)
+	{
+		if (c < 0)
+		{
+			return -1;
+		}
+	}
+
+	se->synced = 1;
+	return 0;
+}
+
+static int cstring(struct serial *se)
+{
+	if (sync_(se) < 0)
+	{
+		return -1;
+	}
+
+	int c;
+
+	while ((c = read_byte(se)) != 0)
+	{
+		if (c < 0)
+		{
+			se->synced = 0;
+			return -1;
+		}
+
+		put_byte(se,c);
+	}
+
+	return 0;
+}
+
+int luaopen_melisma_serial(lua_State *s)
+{
+/*** Read data on serial ports.
+
+	local mserial = require 'melisma.serial'
+
+	mserial.open {
+		path = '/dev/ttyACM0',
+		callback = print,
+	}
+
+@classmod serial
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Open a serial port.
+
+`conf` is a table containing the following keys:
+
+- `path` (**string, required**): Path to serial port (e.g. `/dev/ttyACM0`).
+- `callback` (**function, required**): Callback function for handling messages.
+- `baud` (**integer**); baud rate (default `9600`).
+- `format` (**string**): frame format (default `'8N1'`).
+- `encoding` (**string**): method for encoding messages (default `'cstring'`). May be one of:
+	- `'cstring'`: `NULL`-terminated strings.
+
+@static
+@function open
+@tparam table conf
+@treturn serial
+*/
+	lua_pushcfunction(s,l_open);
+	lua_setfield(s,tbl,"open");
+
+	luaL_newmetatable(s,SERIAL_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_pushvalue(s,tbl);
+	return 1;
+}
diff --git a/mod/spring.c b/mod/spring.c
new file mode 100644
index 0000000..a6f96ea
--- /dev/null
+++ b/mod/spring.c
@@ -0,0 +1,173 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <math.h>
+#include <lauxlib.h>
+#include "melisma.h"
+
+#define SPRING_TYPENAME "spring"
+
+struct spring
+{
+	ml_node  *node;
+	float     target;
+	float     value;
+	float     freq;
+	float     damping;
+	float     velocity;
+	bool      mapped;
+};
+
+static void proc(const ml_proc_args *args)
+{
+	struct spring *spring = args->userp;
+
+	float *out = args->out[0];
+	float *mapped = spring->mapped ? args->in[0] : NULL;
+	float dt = 1.f/ml_sample_rate();
+
+	for (size_t i = 0; i < args->nframes; i++)
+	{
+		float target = mapped ? mapped[i] : spring->target;
+		float w = 2*M_PI*spring->freq;
+		float f = (target - spring->value)*w*w;
+		float d = 2*w*spring->velocity*spring->damping;
+		float a = f - d;
+
+		spring->velocity += a*dt;
+		spring->value += spring->velocity*dt;
+
+		out[i] = spring->value;
+	}
+}
+
+static int l_damping(lua_State *s)
+{
+	struct spring *spring = *(void**) luaL_checkudata(s,1,SPRING_TYPENAME);
+	float x = luaL_checknumber(s,2);
+	spring->damping = x;
+	return 0;
+}
+
+static int l_freq(lua_State *s)
+{
+	struct spring *spring = *(void**) luaL_checkudata(s,1,SPRING_TYPENAME);
+	float x = luaL_checknumber(s,2);
+	spring->freq = x;
+	return 0;
+}
+
+static int l_target(lua_State *s)
+{
+	struct spring *spring = *(void**) luaL_checkudata(s,1,SPRING_TYPENAME);
+	float x = luaL_checknumber(s,2);
+	spring->target = x;
+	return 0;
+}
+
+static int l_map(lua_State *s)
+{
+	struct spring *spring = *(void**) luaL_checkudata(s,1,SPRING_TYPENAME);
+
+	if (spring->mapped)
+	{
+		luaL_error(s,"already mapped");
+	}
+
+	ml_channel *src = *(void**) luaL_checkudata(s,2,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	ml_channel *dst = ml_add_input(spring->node);
+	ml_connect(src,dst);
+
+	spring->mapped = true;
+
+	return 0;
+}
+
+static int l_sample(lua_State *s)
+{
+	struct spring *spring = *(void**) luaL_checkudata(s,1,SPRING_TYPENAME);
+	lua_pushnumber(s,spring->value);
+	return 1;
+}
+
+static int l_call(lua_State *s)
+{
+	struct spring *spring = *(void**) luaL_checkudata(s,1,SPRING_TYPENAME);
+	*(void**) lua_newuserdata(s,sizeof(void*)) = ml_get_output(spring->node,0);
+	luaL_setmetatable(s,MELISMA_OUTPUT_CHANNEL_TYPENAME);
+	return 1;
+}
+
+static int l_init(lua_State *s)
+{
+	float value = luaL_checknumber(s,1);
+	float freq = luaL_checknumber(s,2);
+	float damping = luaL_checknumber(s,3);
+
+	struct spring *spring = calloc(1,sizeof(*spring));
+	spring->value = value;
+	spring->freq = freq;
+	spring->damping = damping;
+	spring->mapped = false;
+
+	spring->node = ml_create_node(proc,spring);
+	ml_add_output(spring->node);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = spring;
+	luaL_setmetatable(s,SPRING_TYPENAME);
+
+	return 1;
+}
+
+int luaopen_melisma_spring(lua_State *s)
+{
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+	lua_pushcfunction(s,l_freq);
+	lua_setfield(s,tbl,"freq");
+
+	lua_pushcfunction(s,l_damping);
+	lua_setfield(s,tbl,"damping");
+
+	lua_pushcfunction(s,l_target);
+	lua_setfield(s,tbl,"target");
+
+	lua_pushcfunction(s,l_sample);
+	lua_setfield(s,tbl,"sample");
+
+	lua_pushcfunction(s,l_map);
+	lua_setfield(s,tbl,"map");
+
+	luaL_newmetatable(s,SPRING_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_pushcfunction(s,l_call);
+	lua_setfield(s,mt,"__call");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/timer.c b/mod/timer.c
new file mode 100644
index 0000000..92659dd
--- /dev/null
+++ b/mod/timer.c
@@ -0,0 +1,152 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <lauxlib.h>
+#include "melisma.h"
+
+#define TIMER_TYPENAME "timer"
+
+struct timer
+{
+	bool     on;
+	uint64_t t;
+};
+
+static void proc(const ml_proc_args *args)
+{
+	struct timer *tmr = args->userp;
+
+	if (tmr->on)
+	{
+		tmr->t += args->nframes;
+	}
+}
+
+static int l_init(lua_State *s)
+{
+	struct timer *tmr = calloc(1,sizeof(*tmr));
+
+	tmr->on = false;
+	tmr->t = 0;
+
+	ml_node *node = ml_create_node(proc,tmr);
+	ml_channel *src = ml_add_output(node);
+	ml_channel *dst = ml_add_input(ml_get_root_node());
+	ml_connect(src,dst);
+
+	*(void**) lua_newuserdata(s,sizeof(void*)) = tmr;
+	luaL_setmetatable(s,TIMER_TYPENAME);
+
+	return 1;
+}
+
+static int l_start(lua_State *s)
+{
+	struct timer *tmr = *(void**) luaL_checkudata(s,1,TIMER_TYPENAME);
+	tmr->on = true;
+	return 0;
+}
+
+static int l_stop(lua_State *s)
+{
+	struct timer *tmr = *(void**) luaL_checkudata(s,1,TIMER_TYPENAME);
+	tmr->on = false;
+	return 0;
+}
+
+static int l_reset(lua_State *s)
+{
+	struct timer *tmr = *(void**) luaL_checkudata(s,1,TIMER_TYPENAME);
+	tmr->t = 0;
+	return 0;
+}
+
+static int l_read(lua_State *s)
+{
+	struct timer *tmr = *(void**) luaL_checkudata(s,1,TIMER_TYPENAME);
+	double t = (double) tmr->t / (double) ml_sample_rate();
+	lua_pushnumber(s,t);
+	return 1;
+}
+
+int luaopen_melisma_timer(lua_State *s)
+{
+/*** Time measurement.
+
+	local mtimer = require 'melisma.timer'
+	local mkeycallback = require 'melisma.keycallback'
+
+	local timer = mtimer.init()
+	timer:start()
+
+	mkeycallback.set(function()
+		print(timer:read())
+		timer:reset()
+	end)
+
+@classmod timer
+*/
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** Create a new timer.
+@static
+@function init
+@treturn timer
+*/
+	lua_pushcfunction(s,l_init);
+	lua_setfield(s,tbl,"init");
+
+/*** Start timer.
+@function start
+*/
+	lua_pushcfunction(s,l_start);
+	lua_setfield(s,tbl,"start");
+
+/*** Stop timer.
+@function stop
+*/
+	lua_pushcfunction(s,l_stop);
+	lua_setfield(s,tbl,"stop");
+
+/*** Reset timer.
+@function reset
+*/
+	lua_pushcfunction(s,l_reset);
+	lua_setfield(s,tbl,"reset");
+
+
+/*** Read timer.
+@function read
+@treturn number Elapsed seconds.
+*/
+	lua_pushcfunction(s,l_read);
+	lua_setfield(s,tbl,"read");
+
+	luaL_newmetatable(s,TIMER_TYPENAME);
+	int mt = lua_gettop(s);
+
+	lua_pushvalue(s,tbl);
+	lua_setfield(s,mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}
diff --git a/mod/udp.c b/mod/udp.c
new file mode 100644
index 0000000..6448a56
--- /dev/null
+++ b/mod/udp.c
@@ -0,0 +1,391 @@
+/*
+ * melisma - extensible and scriptable audio engine
+ * Copyright (C) 2026  Ludvig Gunne Lindström
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+
+#include <unistd.h>
+#include <sys/eventfd.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <lauxlib.h>
+
+#include "melisma.h"
+#include "melisma/ring.h"
+
+#define SOCKADDR_TYPENAME   "sockaddr"
+#define UDP_SOCKET_TYPENAME "udp socket"
+#define UDP_PACKET_SIZE     65536
+
+struct udp_socket
+{
+	int              fd;
+	int              family;
+	int              event;
+	int              bound;
+	int              callb;
+	lua_State       *state;
+	ml_ring         *recvring;
+	ml_ring         *sendring;
+	uint8_t          pollbuf[UDP_PACKET_SIZE];
+	uint8_t          procbuf[UDP_PACKET_SIZE];
+};
+
+// TODO: CHECK BUFFER SIZES FOR ADDRESSES
+
+static int l_sockaddr_unix(lua_State *s)
+{
+	size_t len;
+	const char *path = luaL_checklstring(s,1,&len);
+
+	struct sockaddr_storage *sa = lua_newuserdata(s,sizeof *sa);
+	luaL_setmetatable(s,SOCKADDR_TYPENAME);
+	memset(sa,0,sizeof *sa);
+
+	((struct sockaddr_un*)sa)->sun_family = AF_UNIX;
+	memcpy(((struct sockaddr_un*)sa)->sun_path,path,len);
+
+	return 1;
+}
+
+static int l_sockaddr_inet(lua_State *s)
+{
+	const char *addr = luaL_checkstring(s,1);
+	int port = luaL_checkinteger(s,2);
+
+	struct in_addr in_addr;
+	if (inet_pton(AF_INET,addr,&in_addr) != 1)
+	{
+		luaL_error(s,"invalid ipv4 address '%s'",addr);
+	}
+
+	struct sockaddr_storage *sa = lua_newuserdata(s,sizeof *sa);
+	luaL_setmetatable(s,SOCKADDR_TYPENAME);
+	memset(sa,0,sizeof *sa);
+
+	((struct sockaddr_in*)sa)->sin_family = AF_INET;
+	((struct sockaddr_in*)sa)->sin_port = htons(port);
+	memcpy(&((struct sockaddr_in*)sa)->sin_addr,&in_addr,sizeof in_addr);
+
+	return 1;
+}
+
+static void recv_handler(int fd, int flags, void *args)
+{
+	struct udp_socket *us = args;
+	ssize_t len = recvfrom(fd,us->pollbuf,sizeof us->pollbuf,0,NULL,NULL);
+
+	if (len < 0)
+	{
+		perror("recvfrom");
+		return;
+	}
+
+	if (!ml_ring_has_space(us->recvring,len + sizeof len))
+	{
+		fprintf(stderr,"dropped udp packet");
+	}
+
+	ml_ring_write_blocking(us->recvring,&len,sizeof len);
+	ml_ring_write_blocking(us->recvring,us->pollbuf,len);
+}
+
+static void send_handler(int fd, int flags, void *args)
+{
+	struct udp_socket *us = args;
+
+	size_t sa_len,len;
+	struct sockaddr_storage storage = {0};
+
+	ml_ring_read_blocking(us->sendring,&sa_len,sizeof sa_len);
+	ml_ring_read_blocking(us->sendring,&storage,sa_len);
+	ml_ring_read_blocking(us->sendring,&len,sizeof len);
+	ml_ring_read_blocking(us->sendring,us->pollbuf,len);
+
+	if (sendto(us->fd,us->pollbuf,len,0,(struct sockaddr*) &storage,sa_len) < 0)
+	{
+		perror("sendto");
+	}
+
+	uint64_t x;
+	if (read(us->event,&x,sizeof x) != sizeof x)
+		;
+}
+
+static int l_socket(lua_State *s)
+{
+	int family = lua_tointeger(s,lua_upvalueindex(1));
+	int fd = socket(family,SOCK_DGRAM,0);
+
+	if (fd < 0)
+	{
+		const char *err = strerror(errno);
+		luaL_error(s,"failed to create socket: %s",err);
+	}
+
+	struct udp_socket *us = calloc(1,sizeof(*us));
+	us->fd = fd;
+	us->family = family;
+	us->sendring = ml_ring_init(UDP_PACKET_SIZE);
+	us->event = eventfd(0,EFD_SEMAPHORE);
+
+	ml_add_io_handler(us->event,POLLIN,send_handler,us);
+
+	*(struct udp_socket**) lua_newuserdata(s,sizeof(struct udp_socket*)) = us;
+	luaL_setmetatable(s,UDP_SOCKET_TYPENAME);
+
+	return 1;
+}
+
+static const char *family_name(int family)
+{
+	switch (family)
+	{
+	case AF_UNIX: return "unix";
+	case AF_INET: return "inet";
+	default:      assert(0);
+	}
+}
+
+static void proc(const ml_proc_args *args)
+{
+	struct udp_socket *us = args->userp;
+	ssize_t len;
+
+	while (!ml_ring_empty(us->recvring))
+	{
+		ml_ring_read_blocking(us->recvring,&len,sizeof len);
+		ml_ring_read_blocking(us->recvring,us->procbuf,len);
+
+		lua_pushlstring(us->state,(const char*)us->procbuf,len);
+		int arg = luaL_ref(us->state,LUA_REGISTRYINDEX);
+
+		ml_schedule_event(0,us->callb,arg);
+	}
+}
+
+static size_t get_sockaddr_len(struct sockaddr *sa)
+{
+	if (sa->sa_family == AF_UNIX)
+	{
+		const char *path = ((struct sockaddr_un*)sa)->sun_path;
+
+		if (path[0] == 0 && path[1] != 0)
+		{
+			return offsetof(struct sockaddr_un,sun_path) + strlen(path+1) + 1;
+		}
+
+		return offsetof(struct sockaddr_un,sun_path) + strlen(path);
+	}
+	else
+	{
+		return sizeof(struct sockaddr_in);
+	}
+}
+
+static void check_family(lua_State *s, struct udp_socket *us, struct sockaddr *sa)
+{
+	if (us->family != sa->sa_family)
+	{
+		luaL_error(s,"sockaddr address family (%s) does not match socket address family (%s)",
+		           family_name(sa->sa_family), family_name(us->family));
+	}
+}
+
+static int l_bind(lua_State *s)
+{
+	struct udp_socket *us = *(struct udp_socket**) luaL_checkudata(s,1,UDP_SOCKET_TYPENAME);
+	struct sockaddr *sa = luaL_checkudata(s,2,SOCKADDR_TYPENAME);
+
+	luaL_checktype(s,3,LUA_TFUNCTION);
+
+	if (us->bound)
+	{
+		luaL_error(s,"socket is already bound");
+	}
+
+	check_family(s,us,sa);
+
+	size_t len = get_sockaddr_len(sa);
+
+	if (bind(us->fd,sa,len) < 0)
+	{
+		const char *err = strerror(errno);
+		luaL_error(s,"failed to bind socket: %s",err);
+	}
+
+	us->bound = 1;
+	us->recvring = ml_ring_init(UDP_PACKET_SIZE);
+	us->state = s;
+
+	ml_add_io_handler(us->fd,POLLIN,recv_handler,us);
+
+	lua_pushvalue(s,3);
+	us->callb = luaL_ref(s,LUA_REGISTRYINDEX);
+
+	ml_node *node = ml_create_node(proc,us);
+	ml_channel *src = ml_add_output(node);
+	ml_channel *dst = ml_add_input(ml_get_root_node());
+	ml_connect(src,dst);
+
+	return 0;
+}
+
+static int l_send(lua_State *s)
+{
+	struct udp_socket *us = *(struct udp_socket**) luaL_checkudata(s,1,UDP_SOCKET_TYPENAME);
+	struct sockaddr *sa = luaL_checkudata(s,2,SOCKADDR_TYPENAME);
+	size_t len;
+	const char *data = luaL_checklstring(s,3,&len);
+
+	check_family(s,us,sa);
+
+	size_t sa_len = get_sockaddr_len(sa);
+	size_t full_len = sizeof len + len + sizeof sa_len + sa_len;
+
+	if (!ml_ring_has_space(us->sendring,full_len))
+	{
+		lua_pushboolean(s,0);
+		return 1;
+	}
+
+	ml_ring_write_blocking(us->sendring,&sa_len,sizeof sa_len);
+	ml_ring_write_blocking(us->sendring,sa,sa_len);
+	ml_ring_write_blocking(us->sendring,&len,sizeof len);
+	ml_ring_write_blocking(us->sendring,data,len);
+
+	uint64_t x = 1;
+	if (write(us->event,&x,sizeof x) < sizeof x)
+		;
+
+	lua_pushboolean(s,1);
+	return 1;
+}
+
+int luaopen_melisma_udp(lua_State *s)
+{
+	lua_newtable(s);
+	int tbl = lua_gettop(s);
+
+/*** UDP support.
+
+	local mudp = require 'melisma.udp'
+
+	local addr = mudp.sockaddr.inet('127.0.0.1',8000)
+	local sock = mudp.socket.inet()
+
+	sock:send(addr,'hello')
+	sock:bind(addr,print)
+
+@module udp
+*/
+
+/*** Socket address description.
+@type sockaddr
+*/
+	lua_newtable(s);
+	int sockaddr_tbl = lua_gettop(s);
+
+/*** Create a unix domain address description.
+@static
+@function unix
+@tparam string path
+@treturn sockaddr
+*/
+	lua_pushcfunction(s,l_sockaddr_unix);
+	lua_setfield(s,sockaddr_tbl,"unix");
+
+
+/*** Create a internet domain address description.
+@static
+@function inet
+@tparam string host
+@tparam integer port
+@treturn sockaddr
+*/
+	lua_pushcfunction(s,l_sockaddr_inet);
+	lua_setfield(s,sockaddr_tbl,"inet");
+
+	lua_pushvalue(s,sockaddr_tbl);
+	lua_setfield(s,tbl,"sockaddr");
+
+	luaL_newmetatable(s,SOCKADDR_TYPENAME);
+	int sockaddr_mt = lua_gettop(s);
+
+	lua_pushvalue(s,sockaddr_tbl);
+	lua_setfield(s,sockaddr_mt,"__index");
+
+/*** Handle to a socket.
+@type socket
+*/
+
+	lua_newtable(s);
+	int socket_tbl = lua_gettop(s);
+
+/*** Create a unix domain socket.
+@static
+@function unix
+@treturn socket
+*/
+	lua_pushinteger(s,AF_UNIX);
+	lua_pushcclosure(s,l_socket,1);
+	lua_setfield(s,socket_tbl,"unix");
+
+
+/*** Create an internet domain socket.
+@static
+@function inet
+@treturn socket
+*/
+	lua_pushinteger(s,AF_INET);
+	lua_pushcclosure(s,l_socket,1);
+	lua_setfield(s,socket_tbl,"inet");
+
+/*** Bind a socket to an address.
+@function bind
+@tparam sockaddr addr Address description.
+@tparam function fn Packet callback function.
+*/
+	lua_pushcfunction(s,l_bind);
+	lua_setfield(s,socket_tbl,"bind");
+
+/*** Send a packet on a socket.
+@function send
+@tparam sockaddr addr Address description.
+@tparam string pkt Packet to send.
+*/
+	lua_pushcfunction(s,l_send);
+	lua_setfield(s,socket_tbl,"send");
+
+	lua_pushvalue(s,socket_tbl);
+	lua_setfield(s,tbl,"socket");
+
+	luaL_newmetatable(s,UDP_SOCKET_TYPENAME);
+	int socket_mt = lua_gettop(s);
+
+	lua_pushvalue(s,socket_tbl);
+	lua_setfield(s,socket_mt,"__index");
+
+	lua_settop(s,tbl);
+	return 1;
+}