/usr/share/doc/flex-doc/html/Comments-in-the-Input.html

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<a name="Comments-in-the-Input"></a>
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<p>
Previous: <a href="User-Code-Section.html#User-Code-Section" accesskey="p" rel="prev">User Code Section</a>, Up: <a href="Format.html#Format" accesskey="u" rel="up">Format</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Indices.html#Indices" title="Index" rel="index">Index</a>]</p>
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<a name="Comments-in-the-Input-1"></a>
<h3 class="section">5.4 Comments in the Input</h3>

<a name="index-comments_002c-syntax-of"></a>
<p>Flex supports C-style comments, that is, anything between &lsquo;<samp>/*</samp>&rsquo; and
&lsquo;<samp>*/</samp>&rsquo; is
considered a comment. Whenever flex encounters a comment, it copies the
entire comment verbatim to the generated source code. Comments may
appear just about anywhere, but with the following exceptions:
</p>
<ul>
<li> <a name="index-comments_002c-in-rules-section"></a>
Comments may not appear in the Rules Section wherever flex is expecting
a regular expression. This means comments may not appear at the
beginning of a line, or immediately following a list of scanner states.
</li><li> Comments may not appear on an &lsquo;<samp>%option</samp>&rsquo; line in the Definitions
Section.
</li></ul>

<p>If you want to follow a simple rule, then always begin a comment on a
new line, with one or more whitespace characters before the initial
&lsquo;<samp>/*</samp>&rsquo;).  This rule will work anywhere in the input file.
</p>
<p>All the comments in the following example are valid:
</p>
<a name="index-comments_002c-valid-uses-of"></a>
<a name="index-comments-in-the-input"></a>
<div class="example">
<pre class="verbatim">%{
/* code block */
%}

/* Definitions Section */
%x STATE_X

%%
    /* Rules Section */
ruleA   /* after regex */ { /* code block */ } /* after code block */
        /* Rules Section (indented) */
&lt;STATE_X&gt;{
ruleC   ECHO;
ruleD   ECHO;
%{
/* code block */
%}
}
%%
/* User Code Section */

</pre></div>




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flex-doc 2.6.4-6 / usr / share / doc / flex-doc / html / Comments-in-the-Input.html
