<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Chapter 5. Invoking Happy</title><link rel="stylesheet" href="fptools.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.73.2"><link rel="start" href="index.html" title="Happy User Guide"><link rel="up" href="index.html" title="Happy User Guide"><link rel="prev" href="sec-AttributeGrammarExample.html" title="4.4. Example Attribute Grammars"><link rel="next" href="sec-grammar-files.html" title="Chapter 6. Syntax of Grammar Files"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 5. Invoking <span class="application">Happy</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="sec-AttributeGrammarExample.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="sec-grammar-files.html">Next</a></td></tr></table><hr></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="sec-invoking"></a>Chapter 5. Invoking <span class="application">Happy</span></h2></div></div></div><p>An invocation of <span class="application">Happy</span> has the following syntax:</p><pre class="screen">$ happy [ <span class="emphasis"><em>options</em></span> ] <span class="emphasis"><em>filename</em></span> [ <span class="emphasis"><em>options</em></span> ]</pre><p>All the command line options are optional (!) and may occur
either before or after the input file name. Options that take
arguments may be given multiple times, and the last occurrence
will be the value used.</p><p>There are two types of grammar files,
<code class="filename">file.y</code> and <code class="filename">file.ly</code>, with
the latter observing the reverse comment (or literate) convention
(i.e. each code line must begin with the character
<code class="literal">></code>, lines which don't begin with
<code class="literal">></code> are treated as comments). The examples
distributed with <span class="application">Happy</span> are all of the
.ly form.</p><a class="indexterm" name="id2549225"></a><p>The flags accepted by <span class="application">Happy</span> are as follows:</p><div class="variablelist"><dl><dt><span class="term"><code class="option">-o</code> <em class="replaceable"><code>file</code></em>, </span><span class="term"><code class="option">--outfile</code>=<em class="replaceable"><code>file</code></em></span></dt><dd><p>Specifies the destination of the generated parser module.
If omitted, the parser will be placed in
<em class="replaceable"><code>file</code></em><code class="literal">.hs</code>,
where <em class="replaceable"><code>file</code></em> is the name of the input
file with any extension removed.</p></dd><dt><span class="term"><code class="option">-i</code>[<span class="optional"><em class="replaceable"><code>file</code></em></span>], </span><span class="term"><code class="option">--info</code>[<span class="optional">=<em class="replaceable"><code>file</code></em></span>]</span></dt><dd><a class="indexterm" name="id2549302"></a><p> Directs <span class="application">Happy</span> to produce an info file
containing detailed information about the grammar, parser
states, parser actions, and conflicts. Info files are vital
during the debugging of grammars. The filename argument is
optional (note that there's no space between
<code class="literal">-i</code> and the filename in the short
version), and if omitted the info file will be written to
<em class="replaceable"><code>file</code></em><code class="literal">.info</code> (where
<em class="replaceable"><code>file</code></em> is the input file name with any
extension removed).</p></dd><dt><span class="term"><code class="option">-t</code> <em class="replaceable"><code>dir</code></em>, </span><span class="term"><code class="option">--template</code>=<em class="replaceable"><code>dir</code></em></span></dt><dd><a class="indexterm" name="id2549364"></a><p>Instructs <span class="application">Happy</span> to use this directory
when looking for template files: these files contain the
static code that <span class="application">Happy</span> includes in every
generated parser. You shouldn't need to use this option if
<span class="application">Happy</span> is properly configured for your
computer.</p></dd><dt><span class="term"><code class="option">-m</code> <em class="replaceable"><code>name</code></em>, </span><span class="term"><code class="option">--magic-name</code>=<em class="replaceable"><code>name</code></em></span></dt><dd><p> <span class="application">Happy</span> prefixes all the symbols it uses internally
with either <code class="literal">happy</code> or <code class="literal">Happy</code>. To use a
different string, for example if the use of <code class="literal">happy</code>
is conflicting with one of your own functions, specify the
prefix using the <code class="option">-m</code> option.</p></dd><dt><span class="term"><code class="option">-s</code>, </span><span class="term"><code class="option">--strict</code></span></dt><dd><p>NOTE: the <code class="option">--strict</code> option is
experimental and may cause unpredictable results.</p><p>This option causes the right hand side of each
production (the semantic value) to be evaluated eagerly at
the moment the production is reduced. If the lazy behaviour
is not required, then using this option will improve
performance and may reduce space leaks. Note that the
parser as a whole is never lazy - the whole input will
always be consumed before any input is produced, regardless
of the setting of the <code class="option">--strict</code> flag.</p></dd><dt><span class="term"><code class="option">-g</code>, </span><span class="term"><code class="option">--ghc</code></span></dt><dd><a class="indexterm" name="id2549500"></a><a class="indexterm" name="id2549509"></a><p>Instructs <span class="application">Happy</span> to generate a parser
that uses GHC-specific extensions to obtain faster code.</p></dd><dt><span class="term"><code class="option">-c</code>, </span><span class="term"><code class="option">--coerce</code></span></dt><dd><a class="indexterm" name="id2549545"></a><a class="indexterm" name="id2549554"></a><p> Use GHC's <code class="literal">unsafeCoerce#</code> extension to
generate smaller faster parsers. Type-safety isn't
compromised.</p><p>This option may only be used in conjuction with
<code class="option">-g</code>.</p></dd><dt><span class="term"><code class="option">-a</code>, </span><span class="term"><code class="option">--arrays</code></span></dt><dd><a class="indexterm" name="id2549598"></a><a class="indexterm" name="id2549606"></a><p> Instructs <span class="application">Happy</span> to generate a parser
using an array-based shift reduce parser. When used in
conjunction with <code class="option">-g</code>, the arrays will be
encoded as strings, resulting in faster parsers. Without
<code class="option">-g</code>, standard Haskell arrays will be
used.</p></dd><dt><span class="term"><code class="option">-d</code>, </span><span class="term"><code class="option">--debug</code></span></dt><dd><a class="indexterm" name="id2549652"></a><a class="indexterm" name="id2549661"></a><p>Generate a parser that will print debugging
information to <code class="literal">stderr</code> at run-time,
including all the shifts, reductions, state transitions and
token inputs performed by the parser.</p><p>This option can only be used in conjunction with
<code class="option">-a</code>.</p></dd><dt><span class="term"><code class="option">-?</code>, </span><span class="term"><code class="option">--help</code></span></dt><dd><p>Print usage information on standard output then exit
successfully.</p></dd><dt><span class="term"><code class="option">-V</code>, </span><span class="term"><code class="option">--version</code></span></dt><dd><p>Print version information on standard output then exit
successfully. Note that for legacy reasons <code class="option">-v</code>
is supported, too, but the use of it is deprecated.
<code class="option">-v</code> will be used for verbose mode when it is
actually implemented.</p></dd></dl></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sec-AttributeGrammarExample.html">Prev</a> </td><td width="20%" align="center"> </td><td width="40%" align="right"> <a accesskey="n" href="sec-grammar-files.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">4.4. Example Attribute Grammars </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 6. Syntax of Grammar Files</td></tr></table></div></body></html>
distrib
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Mandriva
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2010.0
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i586
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media
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8de1f55ea6a1a64d0f3f3ea116288458
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files
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