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MLton
20241230
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<h1>LineDirective</h1>
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<p>To aid in the debugging of code produced by program generators such
as <a href="https://www.cs.tufts.edu/~nr/noweb/">Noweb</a>, MLton supports
comments with line directives of the form</p>
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<pre class="rouge highlight"><code data-lang="sml"><span class="c">(*</span><span class="cm">#line l.c "f"*)</span></code></pre>
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<p>Here, <em>l</em> and <em>c</em> are sequences of decimal digits and <em>f</em> is the
source file.  The first character of a source file has the position
1.1.  A line directive causes the front end to believe that the
character following the right parenthesis is at the line and column of
the specified file.  A line directive only affects the reporting of
error messages and does not affect program semantics (except for
functions like <code>MLton.Exn.history</code> that report source file positions).
Syntactically invalid line directives are ignored.  To prevent
incompatibilities with SML, the file name may not contain the
character sequence <code>*)</code>.</p>
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Last updated Thu Oct 21 15:53:06 2021 -0400 by Matthew Fluet.
<a href="https://github.com/MLton/mlton/commits/master/doc/guide/src/LineDirective.adoc">Log</a>
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