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* Chickadee: (chickadee). Game programming toolkit for Guile.
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<a name="Channels-1"></a>
<h4 class="subsection">2.4.4 Channels</h4>
<p>Channels are a tool for communicating amongst different scripts. One
script can write a value to the channel and another can read from it.
Reading or writing to a channel suspends that script until there is
someone on the other end of the line to complete the transaction.
</p>
<p>Here’s a simplistic example:
</p>
<div class="example">
<pre class="example">(define c (make-channel))
(script
(forever
(let ((item (channel-get c)))
(pk 'got item))))
(script
(channel-put c 'sword)
(channel-put c 'shield)
(channel-put c 'potion))
</pre></div>
<dl>
<dt><a name="index-make_002dchannel"></a>Procedure: <strong>make-channel</strong></dt>
<dd><p>Return a new channel
</p></dd></dl>
<dl>
<dt><a name="index-channel_003f"></a>Procedure: <strong>channel?</strong> <em>obj</em></dt>
<dd><p>Return <code>#t</code> if <var>obj</var> is a channel.
</p></dd></dl>
<dl>
<dt><a name="index-channel_002dget"></a>Procedure: <strong>channel-get</strong> <em>channel</em></dt>
<dd><p>Retrieve a value from <var>channel</var>. The current script suspends
until a value is available.
</p></dd></dl>
<dl>
<dt><a name="index-channel_002dput"></a>Procedure: <strong>channel-put</strong> <em>channel data</em></dt>
<dd><p>Send <var>data</var> to <var>channel</var>. The current script suspends until
another script is available to retrieve the value.
</p></dd></dl>
<p>A low-level API also exists for using channels outside of a script via
callback procedures:
</p>
<dl>
<dt><a name="index-channel_002dget_0021"></a>Procedure: <strong>channel-get!</strong> <em>channel proc</em></dt>
<dd><p>Asynchronously retrieve a value from <var>channel</var> and call <var>proc</var>
with that value.
</p></dd></dl>
<dl>
<dt><a name="index-channel_002dput_0021"></a>Procedure: <strong>channel-put!</strong> <em>channel data [thunk]</em></dt>
<dd><p>Asynchronously send <var>data</var> to <var>channel</var> and call <var>thunk</var>
after it has been received.
</p></dd></dl>
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