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<h5 class="subsubsection">2.7.7.2 Note</h5>

<p>This operation allows arbitrary information or comments to be embedded
in a virtual code application in such a way that it will be ignored by
<code>avram</code> when executing it. For the <code>silly</code> language, a
<code>note</code> function is defined in the standard prelude so as to imply
the following theorem. 
<a name="index-g_t_0040code_007bnote_007d-281"></a><a name="index-annotations-282"></a>
     <dl>
<dt><em>T11</em><dd>[[<code>note</code>]] <code>(</code><var>f</var><code>,</code><var>c</var><code>)</code> = <code>((nil,nil),((nil,nil),(nil,(nil,(</code><var>f</var><code>,</code><var>c</var><code>)))))</code>
</dl>

<p class="noindent">Intuitively, the argument <var>f</var> represents a function, and the
argument <code>c</code> represents the comment, annotation, or whatever, that
will be embedded but ignored in the virtual code.

   <p>Semantically, a function with a note attached is the same as the
function by itself, as the following property stipulates for
any non-<code>nil</code> <var>f</var>.

     <dl>
<dt><em>P8</em><dd>([[<code>note</code>]] <code>(</code><var>f</var><code>,</code><var>c</var><code>)</code>) <var>x</var> = <var>f</var> <var>x</var>
</dl>

   <p>A possible reason for using this feature might be to support a language
that performs run-time type checking by hanging type tags on
<a name="index-type-tags-283"></a>everything. Another possible use would be to include symbolic
information needed by a debugger.

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