manuals/sly/Miscellaneous_002dUtilities.html


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<a name="Miscellaneous_002dUtilities"></a>
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Previous: <a href="Live-Reloading.html#Live-Reloading" accesskey="p" rel="prev">Live Reloading</a>, Up: <a href="Utilities.html#Utilities" accesskey="u" rel="up">Utilities</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
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<hr>
<a name="Miscellaneous-2"></a>
<h4 class="subsection">4.6.3 Miscellaneous</h4>

<div class="example">
<pre class="example">(use-modules (sly utils))
</pre></div>

<p>Miscellaneous helpful procedures.
</p>
<dl>
<dt><a name="index-define_002dguardian"></a>Scheme Syntax: <strong>define-guardian</strong> <em><var>name</var> <var>reaper</var></em></dt>
<dd><p>Define a new guardian called <code>name</code> and call <code>reaper</code> when
an object within the guardian is GC&rsquo;d.  Reaping is ensured to happen
from the same thread that is running the game loop.
</p></dd></dl>

<dl>
<dt><a name="index-memoize"></a>Scheme Procedure: <strong>memoize</strong> <em><var>proc</var></em></dt>
<dd><p>Return a memoizing version of <code>proc</code>.
</p></dd></dl>

<dl>
<dt><a name="index-forever"></a>Scheme Syntax: <strong>forever</strong> <em><var>body</var> &hellip;</em></dt>
<dd><p>Evaluate <code>body</code> in an unbounded loop.  Useful in coroutines that
have no end.
</p></dd></dl>

<dl>
<dt><a name="index-trampoline"></a>Scheme Syntax: <strong>trampoline</strong> <em><var>proc-name</var></em></dt>
<dd><p>Create a new procedure that applies the procedure bound to
<code>proc-name</code> with all given arguments.
</p></dd></dl>

<dl>
<dt><a name="index-chain_002a"></a>Scheme Syntax: <strong>chain*</strong> <em><var>args</var> (<var>proc</var> &hellip;) . <var>rest</var></em></dt>
<dd><p>Handy macro for flattening nested procedure calls where the output of
an inner call is the last argument to the outer call.
</p>
<div class="example">
<pre class="example">(chain* (list '(1 2) '(3 4))
  (map +)
  (fold + 0)) ;; =&gt; 10
</pre></div>

</dd></dl>

<dl>
<dt><a name="index-chain"></a>Scheme Syntax: <strong>chain</strong> <em><var>arg</var> (<var>proc</var> &hellip;) . <var>rest</var></em></dt>
<dd><p>Like <code>chain*</code> but for a single argument.
</p>
<div class="example">
<pre class="example">(chain '(1 2 3 4)
  (map 1+)
  (fold + 0)) ;; =&gt; 14
</pre></div>

</dd></dl>

<dl>
<dt><a name="index-list_002d_003evlist_002a"></a>Scheme Procedure: <strong>list-&gt;vlist*</strong> <em><var>lst</var></em></dt>
<dd><p>Convert <code>lst</code> and all sub-lists within to vlists.
</p></dd></dl>

<dl>
<dt><a name="index-list_002d_003evlist_002a-1"></a>Scheme Procedure: <strong>list-&gt;vlist*</strong> <em><var>lst</var> <var>index</var> [&hellip;]</em></dt>
<dd><p>Return the element at index <code>index &hellip;</code> in the nested vlist
structure <code>vlist</code>.
</p></dd></dl>


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