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<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="Docutils 0.14: http://docutils.sourceforge.net/" />
<title>Lrexlib Reference Manual</title>
<link rel="stylesheet" href="lrexlib.css" type="text/css" />
</head>
<body>
<div class="document" id="lrexlib-reference-manual">
<h1 class="title">Lrexlib Reference Manual</h1>
<div class="contents topic" id="table-of-contents">
<p class="topic-title first">Table of Contents</p>
<ul class="simple">
<li><a class="reference internal" href="#notes" id="id16">Notes</a></li>
<li><a class="reference internal" href="#functions-and-methods-common-to-all-bindings" id="id17">Functions and methods common to all bindings</a><ul>
<li><a class="reference internal" href="#match" id="id18">match</a></li>
<li><a class="reference internal" href="#find" id="id19">find</a></li>
<li><a class="reference internal" href="#gmatch" id="id20">gmatch</a></li>
<li><a class="reference internal" href="#gsub" id="id21">gsub</a></li>
<li><a class="reference internal" href="#split" id="id22">split</a></li>
<li><a class="reference internal" href="#count" id="id23">count</a></li>
<li><a class="reference internal" href="#flags" id="id24">flags</a></li>
<li><a class="reference internal" href="#new" id="id25">new</a></li>
<li><a class="reference internal" href="#tfind" id="id26">tfind</a></li>
<li><a class="reference internal" href="#exec" id="id27">exec</a></li>
</ul>
</li>
<li><a class="reference internal" href="#pcre-only-functions-and-methods" id="id28">PCRE-only functions and methods</a><ul>
<li><a class="reference internal" href="#id1" id="id29">new</a></li>
<li><a class="reference internal" href="#fullinfo" id="id30">fullinfo</a></li>
<li><a class="reference internal" href="#dfa-exec" id="id31">dfa_exec</a></li>
<li><a class="reference internal" href="#maketables" id="id32">maketables</a></li>
<li><a class="reference internal" href="#config" id="id33">config</a></li>
<li><a class="reference internal" href="#id3" id="id34">version</a></li>
</ul>
</li>
<li><a class="reference internal" href="#pcre2-only-functions-and-methods" id="id35">PCRE2-only functions and methods</a><ul>
<li><a class="reference internal" href="#id4" id="id36">new</a></li>
<li><a class="reference internal" href="#patterninfo" id="id37">patterninfo</a></li>
<li><a class="reference internal" href="#id6" id="id38">dfa_exec</a></li>
<li><a class="reference internal" href="#jit-compile" id="id39">jit_compile</a></li>
<li><a class="reference internal" href="#id7" id="id40">maketables</a></li>
<li><a class="reference internal" href="#id8" id="id41">config</a></li>
<li><a class="reference internal" href="#id9" id="id42">version</a></li>
</ul>
</li>
<li><a class="reference internal" href="#gnu-only-functions-and-methods" id="id43">GNU-only functions and methods</a><ul>
<li><a class="reference internal" href="#id10" id="id44">new</a></li>
</ul>
</li>
<li><a class="reference internal" href="#oniguruma-only-functions-and-methods" id="id45">Oniguruma-only functions and methods</a><ul>
<li><a class="reference internal" href="#id11" id="id46">new</a></li>
<li><a class="reference internal" href="#setdefaultsyntax" id="id47">setdefaultsyntax</a></li>
<li><a class="reference internal" href="#id12" id="id48">version</a></li>
<li><a class="reference internal" href="#capturecount" id="id49">capturecount</a></li>
</ul>
</li>
<li><a class="reference internal" href="#tre-only-functions-and-methods" id="id50">TRE-only functions and methods</a><ul>
<li><a class="reference internal" href="#id13" id="id51">new</a></li>
<li><a class="reference internal" href="#atfind" id="id52">atfind</a></li>
<li><a class="reference internal" href="#aexec" id="id53">aexec</a></li>
<li><a class="reference internal" href="#have-approx" id="id54">have_approx</a></li>
<li><a class="reference internal" href="#have-backrefs" id="id55">have_backrefs</a></li>
<li><a class="reference internal" href="#id14" id="id56">config</a></li>
<li><a class="reference internal" href="#rex-tre-version" id="id57">rex_tre.version</a></li>
</ul>
</li>
<li><a class="reference internal" href="#incompatibilities-with-previous-versions" id="id58">Incompatibilities with previous versions</a></li>
</ul>
</div>
<hr class="docutils" />
<p><strong>Lrexlib</strong> builds into shared libraries called by default <em>rex_posix.so</em>,
<em>rex_pcre.so</em>, <em>rex_pcre2.so</em>, <em>rex_gnu.so</em>, <em>rex_tre.so</em> and <em>rex_onig.so</em>,
which can be used with <em>require</em>.</p>
<hr class="docutils" />
<div class="section" id="notes">
<h2><a class="toc-backref" href="#id16">Notes</a></h2>
<ol class="arabic">
<li><p class="first">Most functions and methods in Lrexlib have mandatory and optional arguments.
There are no dependencies between arguments in Lrexlib's functions and
methods. Any optional argument can be supplied as <tt class="docutils literal">nil</tt> (or omitted if it
is a trailing argument), the library will then use the default value for that
argument.</p>
</li>
<li><p class="first">This document uses the following syntax for optional arguments: they are
bracketed separately, and commas are left outside brackets, e.g.:</p>
<pre class="literal-block">
MyFunc (arg1, arg2, [arg3], [arg4])
</pre>
</li>
<li><p class="first">Throughout this document (unless it causes ambiguity), the identifier <strong>rex</strong>
is used in place of either <em>rex_posix</em>, <em>rex_pcre</em>, <em>rex_pcre2</em>, <em>rex_gnu</em>,
<em>rex_onig</em> or <em>rex_tre</em>, which are the default namespaces for the corresponding
libraries.</p>
</li>
<li><p class="first">All functions that take a regular expression pattern as an argument will
generate an error if that pattern is found invalid by the regex library.</p>
</li>
<li><p class="first">All functions that take a string-type regex argument accept a compiled regex
too. In this case, the <a class="reference internal" href="#cf">cf</a> and <a class="reference internal" href="#larg">larg</a> arguments are ignored (should
be either supplied as nils or omitted).</p>
</li>
<li><p class="first">All functions that take a string-type subject accept a table or userdata that
has a <tt class="docutils literal">topointer</tt> method and <tt class="docutils literal">__len</tt> metamethod, and take the subject to
be a block of memory starting at the address returned by
<tt class="docutils literal">subject:topointer()</tt> and of length <tt class="docutils literal">#subject</tt>. This works with buffers
objects from the alien library (<a class="reference external" href="https://github.com/mascarenhas/alien">https://github.com/mascarenhas/alien</a>). Note
that special attention is needed with POSIX regex libraries that do not
support <tt class="docutils literal">REG_STARTEND</tt>, and hence need NUL-terminated subjects: the NUL is
not included in the string length, so alien buffers must be wrapped to report
a length that excludes the NUL.</p>
</li>
</ol>
<ol class="arabic" id="cf" start="7">
<li><p class="first">The default value for <em>compilation flags</em> (<em>cf</em>) that Lrexlib uses when
the parameter is not supplied or <tt class="docutils literal">nil</tt> is:</p>
<blockquote>
<ul class="simple">
<li><tt class="docutils literal">REG_EXTENDED</tt> for POSIX and TRE</li>
<li><tt class="docutils literal">0</tt> for PCRE and PCRE2</li>
<li><tt class="docutils literal">ONIG_OPTION_NONE</tt> for Oniguruma</li>
<li><tt class="docutils literal">SYNTAX_POSIX_EXTENDED</tt> for GNU</li>
</ul>
</blockquote>
<p><strong>PCRE</strong>, <strong>PCRE2</strong>, <strong>Oniguruma</strong>: <em>cf</em> may also be supplied as a string,
whose characters stand for compilation flags. Combinations of the following
characters (case sensitive) are supported:</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="19%" />
<col width="22%" />
<col width="22%" />
<col width="37%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head"><strong>Character</strong></th>
<th class="head"><strong>PCRE flag</strong></th>
<th class="head"><strong>PCRE2 flag</strong></th>
<th class="head"><strong>Oniguruma flag</strong></th>
</tr>
</thead>
<tbody valign="top">
<tr><td><strong>i</strong></td>
<td>PCRE_CASELESS</td>
<td>PCRE2_CASELESS</td>
<td>ONIG_OPTION_IGNORECASE</td>
</tr>
<tr><td><strong>m</strong></td>
<td>PCRE_MULTILINE</td>
<td>PCRE2_MULTILINE</td>
<td>ONIG_OPTION_NEGATE_SINGLELINE</td>
</tr>
<tr><td><strong>s</strong></td>
<td>PCRE_DOTALL</td>
<td>PCRE2_DOTALL</td>
<td>ONIG_OPTION_MULTILINE</td>
</tr>
<tr><td><strong>x</strong></td>
<td>PCRE_EXTENDED</td>
<td>PCRE2_EXTENDED</td>
<td>ONIG_OPTION_EXTEND</td>
</tr>
<tr><td><strong>U</strong></td>
<td>PCRE_UNGREEDY</td>
<td>PCRE2_UNGREEDY</td>
<td>n/a</td>
</tr>
<tr><td><strong>X</strong></td>
<td>PCRE_EXTRA</td>
<td>n/a</td>
<td>n/a</td>
</tr>
</tbody>
</table>
</blockquote>
</li>
</ol>
<ol class="arabic" id="ef" start="8">
<li><p class="first">The default value for <em>execution flags</em> (<em>ef</em>) that Lrexlib uses when
the parameter is not supplied or <tt class="docutils literal">nil</tt>, is:</p>
<blockquote>
<ul class="simple">
<li><tt class="docutils literal">0</tt> for standard POSIX regex library</li>
<li><tt class="docutils literal">REG_STARTEND</tt> for those POSIX regex libraries that support it, e.g. Spencer's</li>
<li><tt class="docutils literal">0</tt> for PCRE, PCRE2, Oniguruma and TRE</li>
</ul>
</blockquote>
</li>
</ol>
<ol class="arabic simple" id="larg" start="9">
<li>The notation <em>larg...</em> is used to indicate optional library-specific
arguments, which are documented in the <tt class="docutils literal">new</tt> method of each library.</li>
<li>In the functions searching for multiple matches (<tt class="docutils literal">gmatch</tt>, <tt class="docutils literal">gsub</tt>,
<tt class="docutils literal">split</tt>, <tt class="docutils literal">count</tt>) every empty match adjacent to the previous match
is discarded, e.g. <tt class="docutils literal"><span class="pre">rex.count("abc",".*")</span></tt> will return 1.</li>
</ol>
</div>
<hr class="docutils" />
<div class="section" id="functions-and-methods-common-to-all-bindings">
<h2><a class="toc-backref" href="#id17">Functions and methods common to all bindings</a></h2>
<div class="section" id="match">
<h3><a class="toc-backref" href="#id18">match</a></h3>
<p><tt class="funcdef docutils literal">rex.match (subj, patt, [init], [cf], [ef], <span class="pre">[larg...])</span></tt></p>
<p>or</p>
<p><tt class="funcdef docutils literal">r:match (subj, [init], [ef])</tt></p>
<p>The function searches for the first match of the regexp <em>patt</em> in the string
<em>subj</em>, starting from offset <em>init</em>, subject to flags <em>cf</em> and <em>ef</em>.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="15%" />
<col width="51%" />
<col width="13%" />
<col width="21%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>r</td>
<td>regex object produced by new</td>
<td>userdata</td>
<td>n/a</td>
</tr>
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>patt</td>
<td>regular expression pattern</td>
<td>string
or
userdata</td>
<td>n/a</td>
</tr>
<tr><td>[init]</td>
<td>start offset in the subject
(can be negative)</td>
<td>number</td>
<td>1</td>
</tr>
<tr><td>[cf]</td>
<td>compilation flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#cf">cf</a></td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
<tr><td>[larg...]</td>
<td>library-specific arguments</td>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns on success:</strong></dt>
<dd><ol class="first last arabic simple">
<li>All substring matches ("captures"), in the order they appear in the
pattern. <tt class="docutils literal">false</tt> is returned for sub-patterns that did not participate in
the match. If the pattern specified no captures then the whole matched
substring is returned.</li>
</ol>
</dd>
<dt><strong>Returns on failure:</strong></dt>
<dd><ol class="first last arabic simple">
<li><tt class="docutils literal">nil</tt></li>
</ol>
</dd>
</dl>
</div>
<hr class="docutils" />
<div class="section" id="find">
<h3><a class="toc-backref" href="#id19">find</a></h3>
<p><tt class="funcdef docutils literal">rex.find (subj, patt, [init], [cf], [ef], <span class="pre">[larg...])</span></tt></p>
<p>or</p>
<p><tt class="funcdef docutils literal">r:find (subj, [init], [ef])</tt></p>
<p>The function searches for the first match of the regexp <em>patt</em> in the string
<em>subj</em>, starting from offset <em>init</em>, subject to flags <em>cf</em> and <em>ef</em>.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="15%" />
<col width="51%" />
<col width="13%" />
<col width="21%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>r</td>
<td>regex object produced by new</td>
<td>userdata</td>
<td>n/a</td>
</tr>
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>patt</td>
<td>regular expression pattern</td>
<td>string
or
userdata</td>
<td>n/a</td>
</tr>
<tr><td>[init]</td>
<td>start offset in the subject
(can be negative)</td>
<td>number</td>
<td>1</td>
</tr>
<tr><td>[cf]</td>
<td>compilation flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#cf">cf</a></td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
<tr><td>[larg...]</td>
<td>library-specific arguments</td>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns on success:</strong></dt>
<dd><ol class="first last arabic simple">
<li>The start point of the match (a number).</li>
<li>The end point of the match (a number).</li>
<li>All substring matches ("captures"), in the order they appear in the
pattern. <tt class="docutils literal">false</tt> is returned for sub-patterns that did not participate in
the match.</li>
</ol>
</dd>
<dt><strong>Returns on failure:</strong></dt>
<dd><ol class="first last arabic simple">
<li><tt class="docutils literal">nil</tt></li>
</ol>
</dd>
</dl>
</div>
<hr class="docutils" />
<div class="section" id="gmatch">
<h3><a class="toc-backref" href="#id20">gmatch</a></h3>
<p><tt class="funcdef docutils literal">rex.gmatch (subj, patt, [cf], [ef], <span class="pre">[larg...])</span></tt></p>
<p>The function is intended for use in the <em>generic for</em> Lua construct.
It returns an iterator for repeated matching of the pattern <em>patt</em> in
the string <em>subj</em>, subject to flags <em>cf</em> and <em>ef</em>.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="15%" />
<col width="51%" />
<col width="13%" />
<col width="21%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>patt</td>
<td>regular expression pattern</td>
<td>string
or
userdata</td>
<td>n/a</td>
</tr>
<tr><td>[cf]</td>
<td>compilation flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#cf">cf</a></td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
<tr><td>[larg...]</td>
<td>library-specific arguments</td>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
</blockquote>
<p>The iterator function is called by Lua. On every iteration (that is, on every
match), it returns all captures in the order they appear in the pattern (or the
entire match if the pattern specified no captures). The iteration will continue
till the subject fails to match.</p>
</div>
<hr class="docutils" />
<div class="section" id="gsub">
<h3><a class="toc-backref" href="#id21">gsub</a></h3>
<p><tt class="funcdef docutils literal">rex.gsub (subj, patt, repl, [n], [cf], [ef], <span class="pre">[larg...])</span></tt></p>
<p>This function searches for all matches of the pattern <em>patt</em> in the string
<em>subj</em> and replaces them according to the parameters <em>repl</em> and <em>n</em> (see details
below).</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="11%" />
<col width="42%" />
<col width="31%" />
<col width="16%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>patt</td>
<td>regular expression pattern</td>
<td>string or userdata</td>
<td>n/a</td>
</tr>
<tr><td>repl</td>
<td>substitution source</td>
<td>string, function or table</td>
<td>n/a</td>
</tr>
<tr><td>[n]</td>
<td>maximum number of matches to search
for, or control function, or nil</td>
<td>number or function</td>
<td><tt class="docutils literal">nil</tt></td>
</tr>
<tr><td>[cf]</td>
<td>compilation flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#cf">cf</a></td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
<tr><td>[larg...]</td>
<td>library-specific arguments</td>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns:</strong></dt>
<dd><ol class="first last arabic simple">
<li>The subject string with the substitutions made.</li>
<li>Number of matches found.</li>
<li>Number of substitutions made.</li>
</ol>
</dd>
<dt><strong>Details:</strong></dt>
<dd><p class="first">The parameter <em>repl</em> can be either a string, a function or a table.
On each match made, it is converted into a value <em>repl_out</em> that may be used
for the replacement.</p>
<p><em>repl_out</em> is generated differently depending on the type of <em>repl</em>:</p>
<ol class="arabic simple">
<li>If <em>repl</em> is a <em>string</em> then it is treated as a template for substitution,
where the %X occurences in <em>repl</em> are handled in a special way, depending
on the value of the character X:</li>
</ol>
<blockquote>
<ul class="simple">
<li>if X represents a digit, then each %X occurence is substituted by the
value of the X-th submatch (capture), with the following cases handled
specially:<ul>
<li>each %0 is substituted by the entire match</li>
<li>if the pattern contains no captures, then each %1 is substituted by the
entire match</li>
<li>any other %X where X is greater than the number of captures in the
pattern will generate an error ("invalid capture index")</li>
<li>if the pattern does contain a capture with number X but that capture
didn't participate in the match, then %X is substituted by an empty
string</li>
</ul>
</li>
<li>if X is any non-digit character then %X is substituted by X</li>
</ul>
<p>All parts of <em>repl</em> other than %X are copied to <em>repl_out</em> verbatim.</p>
</blockquote>
<ol class="arabic simple" start="2">
<li>If <em>repl</em> is a <em>function</em> then it is called on each match with the
submatches passed as parameters (if there are no submatches then the entire
match is passed as the only parameter). <em>repl_out</em> is the return value of
the <em>repl</em> call, and is interpreted as follows:</li>
</ol>
<blockquote>
<ul class="simple">
<li>if it is a string or a number (coerced to a string), then the replacement
value is that string;</li>
<li>if it is a <tt class="docutils literal">nil</tt> or a <tt class="docutils literal">false</tt>, then no replacement is to be done;</li>
</ul>
</blockquote>
<ol class="arabic simple" start="3">
<li>If <em>repl</em> is a table then <em>repl_out</em> is <em>repl</em> [m1], where m1 is the first
submatch (or the entire match if there are no submatches), following the
same rules as for the return value of <em>repl</em> call, described in the above
paragraph.</li>
</ol>
<p>Note: Under some circumstances, the value of <em>repl_out</em> may be ignored; see
<a class="reference internal" href="#below">below</a>.</p>
<p>gsub behaves differently depending on the type of <em>n</em>:</p>
<ol class="last arabic simple">
<li>If <em>n</em> is a <em>number</em> then it is treated as the maximum number of matches
to search for (an omitted or <tt class="docutils literal">nil</tt> value means an unlimited number of
matches). On each match, the replacement value is the <em>repl_out</em> string
(see above).</li>
</ol>
</dd>
</dl>
<blockquote id="below">
<ol class="arabic" start="2">
<li><p class="first">If <em>n</em> is a function, then it is called on each match, after <em>repl_out</em> is
produced (so if <em>repl</em> is a function, it will be called prior to the <em>n</em>
call).</p>
<p><em>n</em> receives 3 arguments and returns 2 values. Its arguments are:</p>
<blockquote>
<ol class="arabic simple">
<li>The start offset of the match (a number)</li>
<li>The end offset of the match (a number)</li>
<li><em>repl_out</em></li>
</ol>
</blockquote>
<p>The type of its first return controls the replacement produced by gsub for
the current match:</p>
<blockquote>
<ul class="simple">
<li><tt class="docutils literal">true</tt> -- replace/don't replace, according to <em>repl_out</em>;</li>
<li><tt class="docutils literal">nil</tt>/<tt class="docutils literal">false</tt> -- don't replace;</li>
<li>a string (or a number coerced to a string) -- replace by that string;</li>
</ul>
</blockquote>
<p>The type of its second return controls gsub behavior after the current
match is handled:</p>
<blockquote>
<ul class="simple">
<li><tt class="docutils literal">nil</tt>/<tt class="docutils literal">false</tt> -- no changes: <em>n</em> will be called on the next match;</li>
<li><tt class="docutils literal">true</tt> -- search for an unlimited number of matches; <em>n</em> will not be
called again;</li>
<li>a number -- maximum number of matches to search for, beginning from the
next match; <em>n</em> will not be called again;</li>
</ul>
</blockquote>
</li>
</ol>
</blockquote>
</div>
<hr class="docutils" />
<div class="section" id="split">
<h3><a class="toc-backref" href="#id22">split</a></h3>
<p><tt class="funcdef docutils literal">rex.split (subj, sep, [cf], [ef], <span class="pre">[larg...])</span></tt></p>
<p>The function is intended for use in the <em>generic for</em> Lua construct.
It is used for splitting a subject string <em>subj</em> into parts (<em>sections</em>).
The <em>sep</em> parameter is a regular expression pattern representing
<strong>separators</strong> between the sections.</p>
<p>The function returns an iterator for repeated matching of the pattern <em>sep</em> in
the string <em>subj</em>, subject to flags <em>cf</em> and <em>ef</em>.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="15%" />
<col width="51%" />
<col width="13%" />
<col width="21%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>sep</td>
<td>separator (regular expression
pattern)</td>
<td>string
or
userdata</td>
<td>n/a</td>
</tr>
<tr><td>[cf]</td>
<td>compilation flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#cf">cf</a></td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
<tr><td>[larg...]</td>
<td>library-specific arguments</td>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
</blockquote>
<p><strong>On every iteration pass, the iterator returns:</strong></p>
<blockquote>
<ol class="arabic simple">
<li>A subject section (can be an empty string), followed by</li>
<li>All captures in the order they appear in the <em>sep</em> pattern (or the entire
match if the <em>sep</em> pattern specified no captures). If there is no match
(this can occur only in the last iteration), then nothing is returned after
the subject section.</li>
</ol>
</blockquote>
<p>The iteration will continue till the end of the subject. Unlike <a class="reference internal" href="#gmatch">gmatch</a>, there
will always be at least one iteration pass, even if there are no matches in the
subject.</p>
</div>
<hr class="docutils" />
<div class="section" id="count">
<h3><a class="toc-backref" href="#id23">count</a></h3>
<p><tt class="funcdef docutils literal">rex.count (subj, patt, [cf], [ef], <span class="pre">[larg...])</span></tt></p>
<p>This function counts matches of the pattern <em>patt</em> in the string <em>subj</em>.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="11%" />
<col width="42%" />
<col width="31%" />
<col width="16%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>patt</td>
<td>regular expression pattern</td>
<td>string or userdata</td>
<td>n/a</td>
</tr>
<tr><td>[cf]</td>
<td>compilation flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#cf">cf</a></td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
<tr><td>[larg...]</td>
<td>library-specific arguments</td>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns:</strong></dt>
<dd><ol class="first last arabic simple">
<li>Number of matches found.</li>
</ol>
</dd>
</dl>
</div>
<hr class="docutils" />
<div class="section" id="flags">
<h3><a class="toc-backref" href="#id24">flags</a></h3>
<p><tt class="funcdef docutils literal">rex.flags ([tb])</tt></p>
<p>This function returns a table containing the numeric values of the constants
defined by the used regex library, with the keys being the (string) names of the
constants. If the table argument <em>tb</em> is supplied then it is used as the output
table, otherwise a new table is created.</p>
<p>The constants contained in the returned table can then be used in most functions
and methods where <em>compilation flags</em> or <em>execution flags</em> can be specified.
They can also be used for comparing with return codes of some functions and
methods for determining the reason of failure. For details, see the relevant
regex library's documentation.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="15%" />
<col width="52%" />
<col width="13%" />
<col width="21%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>[tb]</td>
<td>a table for placing results into</td>
<td>table</td>
<td><tt class="docutils literal">nil</tt></td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns:</strong></dt>
<dd><ol class="first last arabic simple">
<li>A table filled with the results.</li>
</ol>
</dd>
</dl>
<p><strong>Notes:</strong>
The keys in the <cite>tb</cite> table are formed from the names of the corresponding
constants in the used library. They are formed as follows:</p>
<ul class="simple">
<li><strong>POSIX</strong>, <strong>TRE</strong>: prefix REG_ is omitted, e.g. REG_ICASE becomes <tt class="docutils literal">"ICASE"</tt>.</li>
<li><strong>PCRE:</strong> prefix PCRE_ is omitted, e.g. PCRE_CASELESS becomes <tt class="docutils literal">"CASELESS"</tt>.</li>
<li><strong>PCRE2:</strong> prefix PCRE2_ is omitted, e.g. PCRE2_CASELESS becomes <tt class="docutils literal">"CASELESS"</tt>.</li>
<li><strong>Oniguruma:</strong> names of constants are converted to strings with no alteration,
but for ONIG_OPTION_xxx constants, alias strings are created additionally,
e.g., the value of ONIG_OPTION_IGNORECASE constant becomes accessible via
either of two keys: <tt class="docutils literal">"ONIG_OPTION_IGNORECASE"</tt> and <tt class="docutils literal">"IGNORECASE"</tt>.</li>
<li><strong>GNU</strong>: the GNU library provides the flags <tt class="docutils literal">not_bol</tt>, which stops a
beginning-of-line anchor from matching at the start of a string, <tt class="docutils literal">not_eol</tt>,
which stops an end-of-line anchor from matching at the end of a string, and
<tt class="docutils literal">backward</tt> which causes the search to be performed backwards (that is, the
pattern is matched from positions starting at the end of the string; however,
the matches themselves are still made forwards), as well as the RE_xxx syntax
specifiers (as defined in regex.h), omitting the RE_ prefix. For example,
RE_SYNTAX_GREP becomes <tt class="docutils literal">SYNTAX_GREP</tt> in Lua.</li>
</ul>
</div>
<hr class="docutils" />
<div class="section" id="new">
<h3><a class="toc-backref" href="#id25">new</a></h3>
<p><tt class="funcdef docutils literal">rex.new (patt, [cf], <span class="pre">[larg...])</span></tt></p>
<p>The function compiles regular expression <em>patt</em> into a regular expression object
whose internal representation is corresponding to the library used. The returned
result then can be used by the methods, e.g. <a class="reference internal" href="#tfind">tfind</a>, <a class="reference internal" href="#exec">exec</a>, etc. Regular
expression objects are automatically garbage collected. See the library-specific
documentation below for details of the library-specific arguments <em>larg...</em>, if
any.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="15%" />
<col width="51%" />
<col width="13%" />
<col width="21%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>patt</td>
<td>regular expression pattern</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>[cf]</td>
<td>compilation flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#cf">cf</a></td>
</tr>
<tr><td>[larg...]</td>
<td>library-specific arguments</td>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns:</strong></dt>
<dd><ol class="first last arabic simple">
<li>Compiled regular expression (a userdata).</li>
</ol>
</dd>
</dl>
</div>
<hr class="docutils" />
<div class="section" id="tfind">
<h3><a class="toc-backref" href="#id26">tfind</a></h3>
<p><tt class="funcdef docutils literal">r:tfind (subj, [init], [ef])</tt></p>
<p>The method searches for the first match of the compiled regexp <em>r</em> in the
string <em>subj</em>, starting from offset <em>init</em>, subject to execution flags <em>ef</em>.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="14%" />
<col width="54%" />
<col width="12%" />
<col width="20%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>r</td>
<td>regex object produced by new</td>
<td>userdata</td>
<td>n/a</td>
</tr>
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>[init]</td>
<td>start offset in the subject
(can be negative)</td>
<td>number</td>
<td>1</td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns on success:</strong></dt>
<dd><ol class="first last arabic simple">
<li>The start point of the match (a number).</li>
<li>The end point of the match (a number).</li>
<li>Substring matches ("captures" in Lua terminology) are returned as a third
result, in a table. This table contains <tt class="docutils literal">false</tt> in the positions where the
corresponding sub-pattern did not participate in the match.<ol class="arabic">
<li><strong>PCRE</strong>, <strong>PCRE2</strong>, <strong>Oniguruma</strong>: if <em>named subpatterns</em> are used then
the table also contains substring matches keyed by their correspondent
subpattern names (strings).</li>
</ol>
</li>
</ol>
</dd>
<dt><strong>Returns on failure:</strong></dt>
<dd><ol class="first last arabic simple">
<li><tt class="docutils literal">nil</tt></li>
</ol>
</dd>
</dl>
</div>
<hr class="docutils" />
<div class="section" id="exec">
<h3><a class="toc-backref" href="#id27">exec</a></h3>
<p><tt class="funcdef docutils literal">r:exec (subj, [init], [ef])</tt></p>
<p>The method searches for the first match of the compiled regexp <em>r</em> in the
string <em>subj</em>, starting from offset <em>init</em>, subject to execution flags <em>ef</em>.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="14%" />
<col width="54%" />
<col width="12%" />
<col width="20%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>r</td>
<td>regex object produced by new</td>
<td>userdata</td>
<td>n/a</td>
</tr>
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>[init]</td>
<td>start offset in the subject
(can be negative)</td>
<td>number</td>
<td>1</td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns on success:</strong></dt>
<dd><ol class="first last arabic simple">
<li>The start point of the first match (a number).</li>
<li>The end point of the first match (a number).</li>
<li>The offsets of substring matches ("captures" in Lua terminology) are
returned as a third result, in a table. This table contains <tt class="docutils literal">false</tt> in the
positions where the corresponding sub-pattern did not participate in the
match.<ol class="arabic">
<li><strong>PCRE</strong>, <strong>PCRE2</strong>, <strong>Oniguruma</strong>: if <em>named subpatterns</em> are used then
the table also contains substring matches keyed by their correspondent
subpattern names (strings).</li>
</ol>
</li>
</ol>
</dd>
<dt><strong>Returns on failure:</strong></dt>
<dd><ol class="first last arabic simple">
<li><tt class="docutils literal">nil</tt></li>
</ol>
</dd>
<dt><strong>Example:</strong></dt>
<dd>If the whole match is at offsets 10,20 and substring matches are at offsets
12,14 and 16,19 then the function returns the following: 10, 20,
{ 12,14,16,19 }.</dd>
</dl>
</div>
</div>
<hr class="docutils" />
<div class="section" id="pcre-only-functions-and-methods">
<h2><a class="toc-backref" href="#id28">PCRE-only functions and methods</a></h2>
<div class="section" id="id1">
<h3><a class="toc-backref" href="#id29">new</a></h3>
<p><tt class="funcdef docutils literal">rex.new (patt, [cf], [lo])</tt></p>
<p>The locale (<em>lo</em>) can be either a string (e.g., "French_France.1252"), or a
userdata obtained from a call to <a class="reference internal" href="#maketables-pcre">maketables</a>. The default value, used when
the parameter is not supplied or <tt class="docutils literal">nil</tt>, is the built-in PCRE set of character
tables.</p>
</div>
<hr class="docutils" />
<div class="section" id="fullinfo">
<h3><a class="toc-backref" href="#id30">fullinfo</a></h3>
<p>[See <em>pcre_fullinfo</em> in the PCRE docs.]</p>
<p><tt class="funcdef docutils literal">r:fullinfo ()</tt></p>
<p>This function returns a table containing information about the compiled pattern.
The keys are strings formed in the following way:
<tt class="docutils literal">PCRE_INFO_CAPTURECOUNT</tt> -> <tt class="docutils literal">"CAPTURECOUNT"</tt>. The values are numbers.</p>
<hr class="docutils" />
</div>
<div class="section" id="dfa-exec">
<span id="dfa-exec-pcre"></span><h3><a class="toc-backref" href="#id31">dfa_exec</a></h3>
<p>[PCRE 6.0 and later. See <em>pcre_dfa_exec</em> in the PCRE docs.]</p>
<p><tt class="funcdef docutils literal">r:dfa_exec (subj, [init], [ef], [ovecsize], [wscount])</tt></p>
<p>The method matches a compiled regular expression <em>r</em> against a given subject
string <em>subj</em>, using a DFA matching algorithm.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="15%" />
<col width="54%" />
<col width="12%" />
<col width="19%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>r</td>
<td>regex object produced by new</td>
<td>userdata</td>
<td>n/a</td>
</tr>
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>[init]</td>
<td>start offset in the subject
(can be negative)</td>
<td>number</td>
<td>1</td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
<tr><td>[ovecsize]</td>
<td>size of the array for result offsets</td>
<td>number</td>
<td>100</td>
</tr>
<tr><td>[wscount]</td>
<td>number of elements in the working
space array</td>
<td>number</td>
<td>50</td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns on success (either full or partial match):</strong></dt>
<dd><ol class="first last arabic simple">
<li>The start point of the matches found (a number).</li>
<li>A table containing the end points of the matches found, the longer matches
first.</li>
<li>The return value of the underlying <em>pcre_dfa_exec</em> call (a number).</li>
</ol>
</dd>
<dt><strong>Returns on failure (no match):</strong></dt>
<dd><ol class="first last arabic simple">
<li><tt class="docutils literal">nil</tt></li>
</ol>
</dd>
<dt><strong>Example:</strong></dt>
<dd>If there are 3 matches found starting at offset 10 and ending at offsets 15, 20
and 25 then the function returns the following: 10, { 25,20,15 }, 3.</dd>
</dl>
<hr class="docutils" />
</div>
<div class="section" id="maketables">
<span id="maketables-pcre"></span><h3><a class="toc-backref" href="#id32">maketables</a></h3>
<p>[See <em>pcre_maketables</em> in the PCRE docs.]</p>
<p><tt class="funcdef docutils literal">rex_pcre.maketables ()</tt></p>
<p>Creates a set of character tables corresponding to the current locale and
returns it as a userdata. The returned value can be passed to any Lrexlib
function accepting the <em>locale</em> parameter.</p>
</div>
<hr class="docutils" />
<div class="section" id="config">
<h3><a class="toc-backref" href="#id33">config</a></h3>
<p>[PCRE 4.0 and later. See <em>pcre_config</em> in the PCRE docs.]</p>
<p><tt class="funcdef docutils literal">rex_pcre.config ([tb])</tt></p>
<p>This function returns a table containing the values of the configuration
parameters used at PCRE library build-time. Those parameters (numbers) are
keyed by their names (strings). If the table argument <em>tb</em> is supplied then it
is used as the output table, else a new table is created.</p>
<hr class="docutils" />
</div>
<div class="section" id="id3">
<span id="version"></span><h3><a class="toc-backref" href="#id34">version</a></h3>
<p>[See <em>pcre_version</em> in the PCRE docs.]</p>
<p><tt class="funcdef docutils literal">rex_pcre.version ()</tt></p>
<p>This function returns a string containing the version of the used PCRE library
and its release date.</p>
</div>
</div>
<hr class="docutils" />
<div class="section" id="pcre2-only-functions-and-methods">
<h2><a class="toc-backref" href="#id35">PCRE2-only functions and methods</a></h2>
<div class="section" id="id4">
<h3><a class="toc-backref" href="#id36">new</a></h3>
<p><tt class="funcdef docutils literal">rex.new (patt, [cf], [lo])</tt></p>
<p>The locale (<em>lo</em>) can be either a string (e.g., "French_France.1252"), or a
userdata obtained from a call to <a class="reference internal" href="#maketables-pcre2">maketables</a>. The default value, used when
the parameter is not supplied or <tt class="docutils literal">nil</tt>, is the built-in PCRE2 set of character
tables.</p>
</div>
<hr class="docutils" />
<div class="section" id="patterninfo">
<h3><a class="toc-backref" href="#id37">patterninfo</a></h3>
<p>[See <em>pcre2_patterninfo</em> in the PCRE2 docs.]</p>
<p><tt class="funcdef docutils literal">r:patterninfo ()</tt></p>
<p>This function returns a table containing information about the compiled pattern.
The keys are strings formed in the following way:
<tt class="docutils literal">PCRE2_INFO_CAPTURECOUNT</tt> -> <tt class="docutils literal">"CAPTURECOUNT"</tt>. The values are numbers.</p>
</div>
<hr class="docutils" />
<div class="section" id="id6">
<h3><a class="toc-backref" href="#id38">dfa_exec</a></h3>
<p>[See <em>pcre2_dfa_exec</em> in the PCRE2 docs.]</p>
<p><tt class="funcdef docutils literal">r:dfa_exec (subj, [init], [ef], [ovecsize], [wscount])</tt></p>
<p>The method matches a compiled regular expression <em>r</em> against a given subject
string <em>subj</em>, using a DFA matching algorithm.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="15%" />
<col width="54%" />
<col width="12%" />
<col width="19%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>r</td>
<td>regex object produced by new</td>
<td>userdata</td>
<td>n/a</td>
</tr>
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>[init]</td>
<td>start offset in the subject
(can be negative)</td>
<td>number</td>
<td>1</td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
<tr><td>[ovecsize]</td>
<td>size of the array for result offsets</td>
<td>number</td>
<td>100</td>
</tr>
<tr><td>[wscount]</td>
<td>number of elements in the working
space array</td>
<td>number</td>
<td>50</td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns on success (either full or partial match):</strong></dt>
<dd><ol class="first last arabic simple">
<li>The start point of the matches found (a number).</li>
<li>A table containing the end points of the matches found, the longer matches
first.</li>
<li>The return value of the underlying <em>pcre_dfa_exec</em> call (a number).</li>
</ol>
</dd>
<dt><strong>Returns on failure (no match):</strong></dt>
<dd><ol class="first last arabic simple">
<li><tt class="docutils literal">nil</tt></li>
</ol>
</dd>
<dt><strong>Example:</strong></dt>
<dd>If there are 3 matches found starting at offset 10 and ending at offsets 15, 20
and 25 then the function returns the following: 10, { 25,20,15 }, 3.</dd>
</dl>
</div>
<hr class="docutils" />
<div class="section" id="jit-compile">
<h3><a class="toc-backref" href="#id39">jit_compile</a></h3>
<p>[See <em>pcre2_jit_compile</em> in the PCRE2 docs.]</p>
<p><tt class="funcdef docutils literal">r:jit_compile ([options])</tt></p>
<p>Parameter <em>options</em> is a number (a bitwise OR of separate options;
it defaults to <tt class="docutils literal">PCRE2_JIT_COMPLETE</tt>).</p>
<p>The method returns <tt class="docutils literal">true</tt> on success or <tt class="docutils literal">false</tt> + error message string on failure.</p>
<hr class="docutils" />
</div>
<div class="section" id="id7">
<span id="maketables-pcre2"></span><h3><a class="toc-backref" href="#id40">maketables</a></h3>
<p>[See <em>pcre2_maketables</em> in the PCRE2 docs.]</p>
<p><tt class="funcdef docutils literal">rex_pcre2.maketables ()</tt></p>
<p>Creates a set of character tables corresponding to the current locale and
returns it as a userdata. The returned value can be passed to any Lrexlib
function accepting the <em>locale</em> parameter.</p>
</div>
<hr class="docutils" />
<div class="section" id="id8">
<h3><a class="toc-backref" href="#id41">config</a></h3>
<p>[See <em>pcre2_config</em> in the PCRE2 docs.]</p>
<p><tt class="funcdef docutils literal">rex_pcre2.config ([tb])</tt></p>
<p>This function returns a table containing the values of the configuration
parameters used at PCRE2 library build-time. Those parameters (numbers) are
keyed by their names (strings). If the table argument <em>tb</em> is supplied then it
is used as the output table, else a new table is created.</p>
</div>
<hr class="docutils" />
<div class="section" id="id9">
<h3><a class="toc-backref" href="#id42">version</a></h3>
<p>[See <em>pcre2_config(PCRE2_CONFIG_VERSION)</em> in the PCRE2 docs.]</p>
<p><tt class="funcdef docutils literal">rex_pcre2.version ()</tt></p>
<p>This function returns a string containing the version of the used PCRE2 library
and its release date.</p>
</div>
</div>
<hr class="docutils" />
<div class="section" id="gnu-only-functions-and-methods">
<h2><a class="toc-backref" href="#id43">GNU-only functions and methods</a></h2>
<div class="section" id="id10">
<h3><a class="toc-backref" href="#id44">new</a></h3>
<p><tt class="funcdef docutils literal">rex.new (patt, [cf], [tr])</tt></p>
<p>If the compilation flags (<em>cf</em>) are not supplied or <tt class="docutils literal">nil</tt>, the default syntax
is <tt class="docutils literal">SYNTAX_POSIX_EXTENDED</tt>. Note that this is not the same as passing a value
of zero, which is the same as <tt class="docutils literal">SYNTAX_EMACS</tt>.</p>
<p>The <em>translation</em> parameter (<em>tr</em>) is a map of eight-bit character codes (0 to
255 inclusive) to 8-bit characters (strings). If this parameter is given, the
pattern is translated at compilation time, and each string to be matched is
translated when it is being matched.</p>
</div>
</div>
<div class="section" id="oniguruma-only-functions-and-methods">
<h2><a class="toc-backref" href="#id45">Oniguruma-only functions and methods</a></h2>
<div class="section" id="id11">
<h3><a class="toc-backref" href="#id46">new</a></h3>
<p><tt class="funcdef docutils literal">rex.new (patt, [cf], [enc], [syn])</tt></p>
<p>The <em>encoding</em> parameter (<em>enc</em>) must be one of the predefined strings that are
formed from the ONIG_ENCODING_xxx identifiers defined in oniguruma.h, by means
of omitting the ONIG_ENCODING_ part. For example, ONIG_ENCODING_UTF8 becomes
<tt class="docutils literal">"UTF8"</tt> on the Lua side. The default value, used when the parameter is not
supplied or <tt class="docutils literal">nil</tt>, is <tt class="docutils literal">"ASCII"</tt>.</p>
<p>If the caller-supplied value of this parameter is not one of the predefined
"encoding" string set, an error is raised.</p>
<p>The <em>syntax</em> parameter (<em>syn</em>) must be one of the predefined strings that are
formed from the ONIG_SYNTAX_xxx identifiers defined in oniguruma.h, by means of
omitting the ONIG_SYNTAX_ part. For example, ONIG_SYNTAX_JAVA becomes
<tt class="docutils literal">"JAVA"</tt> on the Lua side. The default value, used when the parameter is not
supplied or <tt class="docutils literal">nil</tt>, is either <tt class="docutils literal">"RUBY"</tt> (at start-up), or the value set by the
last <a class="reference internal" href="#setdefaultsyntax">setdefaultsyntax</a> call.</p>
<p>If the caller-supplied value of <cite>syntax</cite> parameter is not one of the predefined
"syntax" string set, an error is raised.</p>
</div>
<div class="section" id="setdefaultsyntax">
<h3><a class="toc-backref" href="#id47">setdefaultsyntax</a></h3>
<p><tt class="funcdef docutils literal">rex_onig.setdefaultsyntax (syntax)</tt></p>
<p>This function sets the default syntax for the Oniguruma library, according to the
value of the string syntax. The specified syntax will be further used for
interpreting string regex patterns by all relevant functions, unless the <em>syntax</em>
argument is passed to those functions explicitly.</p>
<p><strong>Returns:</strong> nothing</p>
<p><strong>Examples:</strong></p>
<blockquote>
<ol class="arabic simple">
<li><tt class="docutils literal">rex_onig.setdefaultsyntax ("ASIS") <span class="pre">--</span> use plain text syntax as the default</tt></li>
<li><tt class="docutils literal">rex_onig.setdefaultsyntax ("PERL") <span class="pre">--</span> use PERL regex syntax as the default</tt></li>
</ol>
</blockquote>
</div>
<hr class="docutils" />
<div class="section" id="id12">
<h3><a class="toc-backref" href="#id48">version</a></h3>
<p>[See <em>onig_version</em> in the Oniguruma docs.]</p>
<p><tt class="funcdef docutils literal">rex_onig.version ()</tt></p>
<p>This function returns a string containing the version of the used Oniguruma
library.</p>
</div>
<hr class="docutils" />
<div class="section" id="capturecount">
<h3><a class="toc-backref" href="#id49">capturecount</a></h3>
<p>[See <em>onig_number_of_captures</em> in the Oniguruma docs.]</p>
<p><tt class="funcdef docutils literal">r:capturecount ()</tt></p>
<p>Returns the number of captures in the pattern.</p>
</div>
</div>
<hr class="docutils" />
<div class="section" id="tre-only-functions-and-methods">
<h2><a class="toc-backref" href="#id50">TRE-only functions and methods</a></h2>
<div class="section" id="id13">
<h3><a class="toc-backref" href="#id51">new</a></h3>
<p><tt class="funcdef docutils literal">rex.new (patt, [cf])</tt></p>
</div>
<div class="section" id="atfind">
<h3><a class="toc-backref" href="#id52">atfind</a></h3>
<p><tt class="funcdef docutils literal">r:atfind (subj, params, [init], [ef])</tt></p>
<p>The method searches for the first match of the compiled regexp <em>r</em> in the
string <em>subj</em>, starting from offset <em>init</em>, subject to execution flags <em>ef</em>.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="14%" />
<col width="54%" />
<col width="12%" />
<col width="20%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>r</td>
<td>regex object produced by new</td>
<td>userdata</td>
<td>n/a</td>
</tr>
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>params</td>
<td>Approximate matching parameters.
The values are integers.
The valid string key values are:
<tt class="docutils literal">cost_ins</tt>, <tt class="docutils literal">cost_del</tt>,
<tt class="docutils literal">cost_subst</tt>, <tt class="docutils literal">max_cost</tt>,
<tt class="docutils literal">max_ins</tt>, <tt class="docutils literal">max_del</tt>,
<tt class="docutils literal">max_subst</tt>, <tt class="docutils literal">max_err</tt></td>
<td>table</td>
<td><p class="first">n/a</p>
<p class="last">(Default
value for
a missing
field is 0)</p>
</td>
</tr>
<tr><td>[init]</td>
<td>start offset in the subject
(can be negative)</td>
<td>number</td>
<td>1</td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns on success:</strong></dt>
<dd><ol class="first last arabic simple">
<li>The start point of the match (a number).</li>
<li>The end point of the match (a number).</li>
<li>Substring matches ("captures" in Lua terminology) are returned as a third
result, in the array part of a table. Positions where the corresponding
sub-pattern did not participate in the match contain <tt class="docutils literal">false</tt>.
The hash part of the table contains additional information on the match,
in the following fields: <tt class="docutils literal">cost</tt>, <tt class="docutils literal">num_ins</tt>, <tt class="docutils literal">num_del</tt> and <tt class="docutils literal">num_subst</tt>.</li>
</ol>
</dd>
<dt><strong>Returns on failure:</strong></dt>
<dd><ol class="first last arabic simple">
<li><tt class="docutils literal">nil</tt></li>
</ol>
</dd>
</dl>
</div>
<hr class="docutils" />
<div class="section" id="aexec">
<h3><a class="toc-backref" href="#id53">aexec</a></h3>
<p><tt class="funcdef docutils literal">r:aexec (subj, params, [init], [ef])</tt></p>
<p>The method searches for the first match of the compiled regexp <em>r</em> in the
string <em>subj</em>, starting from offset <em>init</em>, subject to execution flags <em>ef</em>.</p>
<blockquote>
<table border="1" class="docutils">
<colgroup>
<col width="14%" />
<col width="54%" />
<col width="12%" />
<col width="20%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Parameter</th>
<th class="head">Description</th>
<th class="head">Type</th>
<th class="head">Default Value</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>r</td>
<td>regex object produced by new</td>
<td>userdata</td>
<td>n/a</td>
</tr>
<tr><td>subj</td>
<td>subject</td>
<td>string</td>
<td>n/a</td>
</tr>
<tr><td>params</td>
<td>Approximate matching parameters.
The values are integers.
The valid string key values are:
<tt class="docutils literal">cost_ins</tt>, <tt class="docutils literal">cost_del</tt>,
<tt class="docutils literal">cost_subst</tt>, <tt class="docutils literal">max_cost</tt>,
<tt class="docutils literal">max_ins</tt>, <tt class="docutils literal">max_del</tt>,
<tt class="docutils literal">max_subst</tt>, <tt class="docutils literal">max_err</tt></td>
<td>table</td>
<td><p class="first">n/a</p>
<p class="last">(Default
value for
a missing
field is 0)</p>
</td>
</tr>
<tr><td>[init]</td>
<td>start offset in the subject
(can be negative)</td>
<td>number</td>
<td>1</td>
</tr>
<tr><td>[ef]</td>
<td>execution flags (bitwise OR)</td>
<td>number</td>
<td><a class="reference internal" href="#ef">ef</a></td>
</tr>
</tbody>
</table>
</blockquote>
<dl class="docutils">
<dt><strong>Returns on success:</strong></dt>
<dd><ol class="first last arabic simple">
<li>The start point of the first match (a number).</li>
<li>The end point of the first match (a number).</li>
<li>The offsets of substring matches ("captures" in Lua terminology) are
returned as a third result, in the array part of a table. Positions where
the corresponding sub-pattern did not participate in the match contain
<tt class="docutils literal">false</tt>. The hash part of the table contains additional information on
the match, in the following fields: <tt class="docutils literal">cost</tt>, <tt class="docutils literal">num_ins</tt>, <tt class="docutils literal">num_del</tt> and
<tt class="docutils literal">num_subst</tt>.</li>
</ol>
</dd>
<dt><strong>Returns on failure:</strong></dt>
<dd><ol class="first last arabic simple">
<li><tt class="docutils literal">nil</tt></li>
</ol>
</dd>
</dl>
</div>
<hr class="docutils" />
<div class="section" id="have-approx">
<h3><a class="toc-backref" href="#id54">have_approx</a></h3>
<p><tt class="funcdef docutils literal">r:have_approx ()</tt></p>
<p>The method returns <tt class="docutils literal">true</tt> if the compiled pattern uses approximate matching,
and <tt class="docutils literal">false</tt> if not.</p>
</div>
<hr class="docutils" />
<div class="section" id="have-backrefs">
<h3><a class="toc-backref" href="#id55">have_backrefs</a></h3>
<p><tt class="funcdef docutils literal">r:have_backrefs ()</tt></p>
<p>The method returns <tt class="docutils literal">true</tt> if the compiled pattern has back references,
and <tt class="docutils literal">false</tt> if not.</p>
</div>
<hr class="docutils" />
<div class="section" id="id14">
<h3><a class="toc-backref" href="#id56">config</a></h3>
<p>[See <em>tre_config</em> in the TRE docs.]</p>
<p><tt class="funcdef docutils literal">rex_tre.config ([tb])</tt></p>
<p>This function returns a table containing the values of the configuration
parameters used at TRE library build-time. Those parameters are
keyed by their names. If the table argument <em>tb</em> is supplied then it
is used as the output table, else a new table is created.</p>
</div>
<hr class="docutils" />
<div class="section" id="rex-tre-version">
<h3><a class="toc-backref" href="#id57">rex_tre.version</a></h3>
<p>[See <em>tre_version</em> in the TRE docs.]</p>
<p><tt class="funcdef docutils literal">rex_tre.version ()</tt></p>
<p>This function returns a string containing the version of the used TRE library.</p>
</div>
</div>
<hr class="docutils" />
<div class="section" id="incompatibilities-with-previous-versions">
<h2><a class="toc-backref" href="#id58">Incompatibilities with previous versions</a></h2>
<p><strong>Incompatibilities between versions 2.8 and 2.7:</strong></p>
<blockquote>
<ol class="arabic simple">
<li>In the functions searching for multiple matches every empty match adjacent
to the previous match is discarded.</li>
</ol>
</blockquote>
<p><strong>Incompatibilities between versions 2.6 and 2.5:</strong></p>
<blockquote>
<ol class="arabic simple">
<li>Removed function <tt class="docutils literal">plainfind</tt>.</li>
<li>Global variables (e.g. <em>rex_posix</em>, <em>rex_pcre</em>, etc.) are not created
by default. This can be changed at the stage of compilation by adding
<tt class="docutils literal"><span class="pre">-DREX_CREATEGLOBALVAR</span></tt> to <tt class="docutils literal">CFLAGS</tt>.</li>
</ol>
</blockquote>
<p><strong>Incompatibilities between versions 2.2 and 2.1:</strong></p>
<blockquote>
<ol class="arabic simple">
<li><a class="reference internal" href="#gsub">gsub</a>: a special "break" return of <em>repl</em> function is deprecated.</li>
<li>(PCRE) <a class="reference internal" href="#gsub">gsub</a>, <a class="reference internal" href="#gmatch">gmatch</a>: after finding an empty match at the current
position, the functions try to find a non-empty match anchored to the same
position.</li>
</ol>
</blockquote>
<p><strong>Incompatibilities between versions 2.1 and 2.0:</strong></p>
<blockquote>
<ol class="arabic simple">
<li><a class="reference internal" href="#match">match</a>, <a class="reference internal" href="#find">find</a>, <a class="reference internal" href="#tfind">tfind</a>, <a class="reference internal" href="#exec">exec</a>, <a class="reference internal" href="#dfa-exec-pcre">dfa_exec</a>: only one value (a <tt class="docutils literal">nil</tt>) is
returned when the subject does not match the pattern. Any other failure
generates an error.</li>
</ol>
</blockquote>
<p><strong>Incompatibilities between versions 2.0 and 1.19:</strong></p>
<blockquote>
<ol class="arabic simple">
<li>Lua 5.1 is required</li>
<li>Functions <tt class="docutils literal">newPCRE</tt> and <tt class="docutils literal">newPOSIX</tt> renamed to new</li>
<li>Functions <tt class="docutils literal">flagsPCRE</tt> and <tt class="docutils literal">flagsPOSIX</tt> renamed to <a class="reference internal" href="#flags">flags</a></li>
<li>Function <tt class="docutils literal">versionPCRE</tt> renamed to <a class="reference internal" href="#version">version</a></li>
<li>Method <tt class="docutils literal">match</tt> renamed to <a class="reference internal" href="#tfind">tfind</a></li>
<li>Method <tt class="docutils literal">gmatch</tt> removed (similar functionality is provided by function
<a class="reference internal" href="#gmatch">gmatch</a>)</li>
<li>Methods <a class="reference internal" href="#tfind">tfind</a> and <a class="reference internal" href="#exec">exec</a>: 2 values are returned on failure</li>
<li>(PCRE) <a class="reference internal" href="#exec">exec</a>: the returned table may additionally contain <em>named
subpatterns</em></li>
</ol>
</blockquote>
</div>
</div>
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Generated on: 2017-11-06 16:45 UTC.
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