boostorg/regex
1
0
Fork 1
mirror of https://github.com/boostorg/regex.git synced 2025-07-05 08:36:31 +02:00
Code Issues Packages Projects Releases Wiki Activity

Merge regex changes from Trunk.

Browse Source 
[SVN r76192]
This commit is contained in:
John Maddock
2011-12-26 18:28:30 +00:00
parent e0fe0863ad
commit 090520dbb4
47 changed files with 1551 additions and 1524 deletions
Download Patch File Download Diff File Expand all files Collapse all files

205
doc/html/boost_regex/syntax/basic_extended.html
View File

@ -27,9 +27,9 @@
<a name="boost_regex.syntax.basic_extended"></a><a class="link" href="basic_extended.html" title="POSIX Extended Regular Expression Syntax">POSIX Extended Regular
Expression Syntax</a>
</h3></div></div></div>
<a name="boost_regex.syntax.basic_extended.synopsis"></a><h4>
<a name="boost_regex.syntax.basic_extended.synopsis-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.synopsis">Synopsis</a>
<h4>
<a name="boost_regex.syntax.basic_extended.h0"></a>
<span><a name="boost_regex.syntax.basic_extended.synopsis"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.synopsis">Synopsis</a>
</h4>
<p>
The POSIX-Extended regular expression syntax is supported by the POSIX C
@ -43,19 +43,19 @@
<span class="comment">// e2 a case insensitive POSIX-Extended expression:</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span> <span class="identifier">e2</span><span class="special">(</span><span class="identifier">my_expression</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span><span class="special">::</span><span class="identifier">extended</span><span class="special">|</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span><span class="special">::</span><span class="identifier">icase</span><span class="special">);</span>
</pre>
<a name="boost_regex.posix_extended_syntax"></a><a name="boost_regex.syntax.basic_extended.posix_extended_syntax"></a><h4>
<a name="boost_regex.syntax.basic_extended.posix_extended_syntax-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.posix_extended_syntax">POSIX
Extended Syntax</a>
<a name="boost_regex.posix_extended_syntax"></a><h4>
<a name="boost_regex.syntax.basic_extended.h1"></a>
<span><a name="boost_regex.syntax.basic_extended.posix_extended_syntax"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.posix_extended_syntax">POSIX Extended
Syntax</a>
</h4>
<p>
In POSIX-Extended regular expressions, all characters match themselves except
for the following special characters:
</p>
<pre class="programlisting">.[{}()\*+?|^$</pre>
<a name="boost_regex.syntax.basic_extended.wildcard_"></a><h5>
<a name="boost_regex.syntax.basic_extended.wildcard_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.wildcard_">Wildcard:</a>
<h5>
<a name="boost_regex.syntax.basic_extended.h2"></a>
<span><a name="boost_regex.syntax.basic_extended.wildcard_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.wildcard_">Wildcard:</a>
</h5>
<p>
The single character '.' when used outside of a character set will match
@ -71,9 +71,9 @@
is passed to the matching algorithms.
</li>
</ul></div>
<a name="boost_regex.syntax.basic_extended.anchors_"></a><h5>
<a name="boost_regex.syntax.basic_extended.anchors_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.anchors_">Anchors:</a>
<h5>
<a name="boost_regex.syntax.basic_extended.h3"></a>
<span><a name="boost_regex.syntax.basic_extended.anchors_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.anchors_">Anchors:</a>
</h5>
<p>
A '^' character shall match the start of a line when used as the first character
@ -83,9 +83,9 @@
A '$' character shall match the end of a line when used as the last character
of an expression, or the last character of a sub-expression.
</p>
<a name="boost_regex.syntax.basic_extended.marked_sub_expressions_"></a><h5>
<a name="boost_regex.syntax.basic_extended.marked_sub_expressions_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.marked_sub_expressions_">Marked
<h5>
<a name="boost_regex.syntax.basic_extended.h4"></a>
<span><a name="boost_regex.syntax.basic_extended.marked_sub_expressions_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.marked_sub_expressions_">Marked
sub-expressions:</a>
</h5>
<p>
@ -95,9 +95,9 @@
matching algorithms. Marked sub-expressions can also repeated, or referred
to by a back-reference.
</p>
<a name="boost_regex.syntax.basic_extended.repeats_"></a><h5>
<a name="boost_regex.syntax.basic_extended.repeats_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.repeats_">Repeats:</a>
<h5>
<a name="boost_regex.syntax.basic_extended.h5"></a>
<span><a name="boost_regex.syntax.basic_extended.repeats_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.repeats_">Repeats:</a>
</h5>
<p>
Any atom (a single character, a marked sub-expression, or a character class)
@ -181,9 +181,10 @@ cab
Will raise an error, as there is nothing for the <code class="computeroutput"><span class="special">*</span></code>
operator to be applied to.
</p>
<a name="boost_regex.syntax.basic_extended.back_references_"></a><h5>
<a name="boost_regex.syntax.basic_extended.back_references_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.back_references_">Back references:</a>
<h5>
<a name="boost_regex.syntax.basic_extended.h6"></a>
<span><a name="boost_regex.syntax.basic_extended.back_references_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.back_references_">Back
references:</a>
</h5>
<p>
An escape character followed by a digit <span class="emphasis"><em>n</em></span>, where <span class="emphasis"><em>n</em></span>
@ -211,9 +212,9 @@ cab
regular expressions, this is a compatible extension to that standard.
</p></td></tr>
</table></div>
<a name="boost_regex.syntax.basic_extended.alternation"></a><h5>
<a name="boost_regex.syntax.basic_extended.alternation-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.alternation">Alternation</a>
<h5>
<a name="boost_regex.syntax.basic_extended.h7"></a>
<span><a name="boost_regex.syntax.basic_extended.alternation"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.alternation">Alternation</a>
</h5>
<p>
The <code class="computeroutput"><span class="special">|</span></code> operator will match either
@ -224,9 +225,9 @@ cab
Parenthesis can be used to group alternations, for example: <code class="computeroutput"><span class="identifier">ab</span><span class="special">(</span><span class="identifier">d</span><span class="special">|</span><span class="identifier">ef</span><span class="special">)</span></code>
will match either of "abd" or "abef".
</p>
<a name="boost_regex.syntax.basic_extended.character_sets_"></a><h5>
<a name="boost_regex.syntax.basic_extended.character_sets_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.character_sets_">Character
<h5>
<a name="boost_regex.syntax.basic_extended.h8"></a>
<span><a name="boost_regex.syntax.basic_extended.character_sets_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.character_sets_">Character
sets:</a>
</h5>
<p>
@ -237,18 +238,17 @@ cab
<p>
A bracket expression may contain any combination of the following:
</p>
<a name="boost_regex.syntax.basic_extended.single_characters_"></a><h6>
<a name="boost_regex.syntax.basic_extended.single_characters_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.single_characters_">Single
characters:</a>
<h6>
<a name="boost_regex.syntax.basic_extended.h9"></a>
<span><a name="boost_regex.syntax.basic_extended.single_characters_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.single_characters_">Single characters:</a>
</h6>
<p>
For example <code class="computeroutput"><span class="special">[</span><span class="identifier">abc</span><span class="special">]</span></code>, will match any of the characters 'a', 'b',
or 'c'.
</p>
<a name="boost_regex.syntax.basic_extended.character_ranges_"></a><h6>
<a name="boost_regex.syntax.basic_extended.character_ranges_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.character_ranges_">Character
<h6>
<a name="boost_regex.syntax.basic_extended.h10"></a>
<span><a name="boost_regex.syntax.basic_extended.character_ranges_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.character_ranges_">Character
ranges:</a>
</h6>
<p>
@ -262,18 +262,18 @@ cab
which case whether a character appears within a range is determined by comparing
the code points of the characters only.
</p>
<a name="boost_regex.syntax.basic_extended.negation_"></a><h6>
<a name="boost_regex.syntax.basic_extended.negation_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.negation_">Negation:</a>
<h6>
<a name="boost_regex.syntax.basic_extended.h11"></a>
<span><a name="boost_regex.syntax.basic_extended.negation_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.negation_">Negation:</a>
</h6>
<p>
If the bracket-expression begins with the ^ character, then it matches the
complement of the characters it contains, for example <code class="computeroutput"><span class="special">[^</span><span class="identifier">a</span><span class="special">-</span><span class="identifier">c</span><span class="special">]</span></code> matches any character that is not in the
range <code class="computeroutput"><span class="identifier">a</span><span class="special">-</span><span class="identifier">c</span></code>.
</p>
<a name="boost_regex.syntax.basic_extended.character_classes_"></a><h6>
<a name="boost_regex.syntax.basic_extended.character_classes_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.character_classes_">Character
<h6>
<a name="boost_regex.syntax.basic_extended.h12"></a>
<span><a name="boost_regex.syntax.basic_extended.character_classes_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.character_classes_">Character
classes:</a>
</h6>
<p>
@ -281,9 +281,9 @@ cab
matches the named character class "name", for example <code class="computeroutput"><span class="special">[[:</span><span class="identifier">lower</span><span class="special">:]]</span></code> matches any lower case character. See
<a class="link" href="character_classes.html" title="Character Class Names">character class names</a>.
</p>
<a name="boost_regex.syntax.basic_extended.collating_elements_"></a><h6>
<a name="boost_regex.syntax.basic_extended.collating_elements_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.collating_elements_">Collating
<h6>
<a name="boost_regex.syntax.basic_extended.h13"></a>
<span><a name="boost_regex.syntax.basic_extended.collating_elements_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.collating_elements_">Collating
Elements:</a>
</h6>
<p>
@ -309,9 +309,9 @@ cab
<p>
matches a NUL character.
</p>
<a name="boost_regex.syntax.basic_extended.equivalence_classes_"></a><h6>
<a name="boost_regex.syntax.basic_extended.equivalence_classes_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.equivalence_classes_">Equivalence
<h6>
<a name="boost_regex.syntax.basic_extended.h14"></a>
<span><a name="boost_regex.syntax.basic_extended.equivalence_classes_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.equivalence_classes_">Equivalence
classes:</a>
</h6>
<p>
@ -326,17 +326,17 @@ cab
this feature can not be relied upon to work portably across all platforms,
or even all locales on one platform.
</p>
<a name="boost_regex.syntax.basic_extended.combinations_"></a><h6>
<a name="boost_regex.syntax.basic_extended.combinations_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.combinations_">Combinations:</a>
<h6>
<a name="boost_regex.syntax.basic_extended.h15"></a>
<span><a name="boost_regex.syntax.basic_extended.combinations_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.combinations_">Combinations:</a>
</h6>
<p>
All of the above can be combined in one character set declaration, for example:
<code class="computeroutput"><span class="special">[[:</span><span class="identifier">digit</span><span class="special">:]</span><span class="identifier">a</span><span class="special">-</span><span class="identifier">c</span><span class="special">[.</span><span class="identifier">NUL</span><span class="special">.]]</span></code>.
</p>
<a name="boost_regex.syntax.basic_extended.escapes"></a><h5>
<a name="boost_regex.syntax.basic_extended.escapes-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.escapes">Escapes</a>
<h5>
<a name="boost_regex.syntax.basic_extended.h16"></a>
<span><a name="boost_regex.syntax.basic_extended.escapes"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.escapes">Escapes</a>
</h5>
<p>
The POSIX standard defines no escape sequences for POSIX-Extended regular
@ -360,9 +360,9 @@ cab
However, that's rather restrictive, so the following standard-compatible
extensions are also supported by Boost.Regex:
</p>
<a name="boost_regex.syntax.basic_extended.escapes_matching_a_specific_character"></a><h6>
<a name="boost_regex.syntax.basic_extended.escapes_matching_a_specific_character-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.escapes_matching_a_specific_character">Escapes
<h6>
<a name="boost_regex.syntax.basic_extended.h17"></a>
<span><a name="boost_regex.syntax.basic_extended.escapes_matching_a_specific_character"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.escapes_matching_a_specific_character">Escapes
matching a specific character</a>
</h6>
<p>
@ -549,9 +549,9 @@ cab
</tr>
</tbody>
</table></div>
<a name="boost_regex.syntax.basic_extended._quot_single_character_quot__character_classes_"></a><h6>
<a name="boost_regex.syntax.basic_extended._quot_single_character_quot__character_classes_-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended._quot_single_character_quot__character_classes_">"Single
<h6>
<a name="boost_regex.syntax.basic_extended.h18"></a>
<span><a name="boost_regex.syntax.basic_extended._quot_single_character_quot__character_classes_"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended._quot_single_character_quot__character_classes_">"Single
character" character classes:</a>
</h6>
<p>
@ -703,9 +703,9 @@ cab
</tr>
</tbody>
</table></div>
<a name="boost_regex.syntax.basic_extended.character_properties"></a><h6>
<a name="boost_regex.syntax.basic_extended.character_properties-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.character_properties">Character
<h6>
<a name="boost_regex.syntax.basic_extended.h19"></a>
<span><a name="boost_regex.syntax.basic_extended.character_properties"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.character_properties">Character
Properties</a>
</h6>
<p>
@ -810,9 +810,10 @@ cab
For example <code class="computeroutput"><span class="special">\</span><span class="identifier">pd</span></code>
matches any "digit" character, as does <code class="computeroutput"><span class="special">\</span><span class="identifier">p</span><span class="special">{</span><span class="identifier">digit</span><span class="special">}</span></code>.
</p>
<a name="boost_regex.syntax.basic_extended.word_boundaries"></a><h6>
<a name="boost_regex.syntax.basic_extended.word_boundaries-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.word_boundaries">Word Boundaries</a>
<h6>
<a name="boost_regex.syntax.basic_extended.h20"></a>
<span><a name="boost_regex.syntax.basic_extended.word_boundaries"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.word_boundaries">Word
Boundaries</a>
</h6>
<p>
The following escape sequences match the boundaries of words:
@ -885,9 +886,9 @@ cab
</tr>
</tbody>
</table></div>
<a name="boost_regex.syntax.basic_extended.buffer_boundaries"></a><h6>
<a name="boost_regex.syntax.basic_extended.buffer_boundaries-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.buffer_boundaries">Buffer
<h6>
<a name="boost_regex.syntax.basic_extended.h21"></a>
<span><a name="boost_regex.syntax.basic_extended.buffer_boundaries"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.buffer_boundaries">Buffer
boundaries</a>
</h6>
<p>
@ -976,9 +977,9 @@ cab
</tr>
</tbody>
</table></div>
<a name="boost_regex.syntax.basic_extended.continuation_escape"></a><h6>
<a name="boost_regex.syntax.basic_extended.continuation_escape-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.continuation_escape">Continuation
<h6>
<a name="boost_regex.syntax.basic_extended.h22"></a>
<span><a name="boost_regex.syntax.basic_extended.continuation_escape"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.continuation_escape">Continuation
Escape</a>
</h6>
<p>
@ -988,9 +989,9 @@ cab
iterating over the matches contained within a text, and you want each subsequence
match to start where the last one ended.
</p>
<a name="boost_regex.syntax.basic_extended.quoting_escape"></a><h6>
<a name="boost_regex.syntax.basic_extended.quoting_escape-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.quoting_escape">Quoting
<h6>
<a name="boost_regex.syntax.basic_extended.h23"></a>
<span><a name="boost_regex.syntax.basic_extended.quoting_escape"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.quoting_escape">Quoting
escape</a>
</h6>
<p>
@ -1002,9 +1003,9 @@ cab
<pre class="programlisting"><span class="special">\*+</span><span class="identifier">a</span>
<span class="special">\*+</span><span class="identifier">aaa</span>
</pre>
<a name="boost_regex.syntax.basic_extended.unicode_escapes"></a><h6>
<a name="boost_regex.syntax.basic_extended.unicode_escapes-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.unicode_escapes">Unicode
<h6>
<a name="boost_regex.syntax.basic_extended.h24"></a>
<span><a name="boost_regex.syntax.basic_extended.unicode_escapes"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.unicode_escapes">Unicode
escapes</a>
</h6>
<div class="informaltable"><table class="table">
@ -1053,18 +1054,18 @@ cab
</tr>
</tbody>
</table></div>
<a name="boost_regex.syntax.basic_extended.any_other_escape"></a><h6>
<a name="boost_regex.syntax.basic_extended.any_other_escape-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.any_other_escape">Any other
escape</a>
<h6>
<a name="boost_regex.syntax.basic_extended.h25"></a>
<span><a name="boost_regex.syntax.basic_extended.any_other_escape"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.any_other_escape">Any
other escape</a>
</h6>
<p>
Any other escape sequence matches the character that is escaped, for example
\@ matches a literal '@'.
</p>
<a name="boost_regex.syntax.basic_extended.operator_precedence"></a><h5>
<a name="boost_regex.syntax.basic_extended.operator_precedence-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.operator_precedence">Operator
<h5>
<a name="boost_regex.syntax.basic_extended.h26"></a>
<span><a name="boost_regex.syntax.basic_extended.operator_precedence"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.operator_precedence">Operator
precedence</a>
</h5>
<p>
@ -1099,9 +1100,9 @@ cab
Alternation <code class="computeroutput"><span class="special">|</span></code>
</li>
</ol></div>
<a name="boost_regex.syntax.basic_extended.what_gets_matched"></a><h5>
<a name="boost_regex.syntax.basic_extended.what_gets_matched-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.what_gets_matched">What
<h5>
<a name="boost_regex.syntax.basic_extended.h27"></a>
<span><a name="boost_regex.syntax.basic_extended.what_gets_matched"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.what_gets_matched">What
Gets Matched</a>
</h5>
<p>
@ -1109,13 +1110,13 @@ cab
possible match is obtained using the <a class="link" href="leftmost_longest_rule.html" title="The Leftmost Longest Rule">leftmost-longest
rule</a>.
</p>
<a name="boost_regex.syntax.basic_extended.variations"></a><h4>
<a name="boost_regex.syntax.basic_extended.variations-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.variations">Variations</a>
<h4>
<a name="boost_regex.syntax.basic_extended.h28"></a>
<span><a name="boost_regex.syntax.basic_extended.variations"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.variations">Variations</a>
</h4>
<a name="boost_regex.syntax.basic_extended.egrep"></a><h5>
<a name="boost_regex.syntax.basic_extended.egrep-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.egrep">Egrep</a>
<h5>
<a name="boost_regex.syntax.basic_extended.h29"></a>
<span><a name="boost_regex.syntax.basic_extended.egrep"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.egrep">Egrep</a>
</h5>
<p>
When an expression is compiled with the <a class="link" href="../ref/syntax_option_type.html" title="syntax_option_type">flag
@ -1134,9 +1135,9 @@ cab
<code class="computeroutput"><span class="identifier">egrep</span></code>, and with grep when
used with the -E option.
</p>
<a name="boost_regex.syntax.basic_extended.awk"></a><h5>
<a name="boost_regex.syntax.basic_extended.awk-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.awk">awk</a>
<h5>
<a name="boost_regex.syntax.basic_extended.h30"></a>
<span><a name="boost_regex.syntax.basic_extended.awk"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.awk">awk</a>
</h5>
<p>
In addition to the <a class="link" href="basic_extended.html#boost_regex.posix_extended_syntax">POSIX-Extended
@ -1148,9 +1149,9 @@ cab
specification are required to be supported - however Boost.Regex supports
these by default anyway.
</p>
<a name="boost_regex.syntax.basic_extended.options"></a><h4>
<a name="boost_regex.syntax.basic_extended.options-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.options">Options</a>
<h4>
<a name="boost_regex.syntax.basic_extended.h31"></a>
<span><a name="boost_regex.syntax.basic_extended.options"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.options">Options</a>
</h4>
<p>
There are a <a class="link" href="../ref/syntax_option_type/syntax_option_type_extended.html" title="Options for POSIX Extended Regular Expressions">variety
@ -1161,9 +1162,9 @@ cab
and <code class="computeroutput"><span class="identifier">icase</span></code> options</a>
modify how the case and locale sensitivity are to be applied.
</p>
<a name="boost_regex.syntax.basic_extended.references"></a><h4>
<a name="boost_regex.syntax.basic_extended.references-heading"></a>
<a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.references">References</a>
<h4>
<a name="boost_regex.syntax.basic_extended.h32"></a>
<span><a name="boost_regex.syntax.basic_extended.references"></a></span><a class="link" href="basic_extended.html#boost_regex.syntax.basic_extended.references">References</a>
</h4>
<p>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap09.html" target="_top">IEEE

135
doc/html/boost_regex/syntax/basic_syntax.html
View File

@ -27,9 +27,9 @@
<a name="boost_regex.syntax.basic_syntax"></a><a class="link" href="basic_syntax.html" title="POSIX Basic Regular Expression Syntax">POSIX Basic Regular
Expression Syntax</a>
</h3></div></div></div>
<a name="boost_regex.syntax.basic_syntax.synopsis"></a><h4>
<a name="boost_regex.syntax.basic_syntax.synopsis-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.synopsis">Synopsis</a>
<h4>
<a name="boost_regex.syntax.basic_syntax.h0"></a>
<span><a name="boost_regex.syntax.basic_syntax.synopsis"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.synopsis">Synopsis</a>
</h4>
<p>
The POSIX-Basic regular expression syntax is used by the Unix utility <code class="computeroutput"><span class="identifier">sed</span></code>, and variations are used by <code class="computeroutput"><span class="identifier">grep</span></code> and <code class="computeroutput"><span class="identifier">emacs</span></code>.
@ -42,9 +42,9 @@
<span class="comment">// e2 a case insensitive POSIX-Basic expression:</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span> <span class="identifier">e2</span><span class="special">(</span><span class="identifier">my_expression</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span><span class="special">::</span><span class="identifier">basic</span><span class="special">|</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span><span class="special">::</span><span class="identifier">icase</span><span class="special">);</span>
</pre>
<a name="boost_regex.posix_basic"></a><a name="boost_regex.syntax.basic_syntax.posix_basic_syntax"></a><h4>
<a name="boost_regex.syntax.basic_syntax.posix_basic_syntax-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.posix_basic_syntax">POSIX
<a name="boost_regex.posix_basic"></a><h4>
<a name="boost_regex.syntax.basic_syntax.h1"></a>
<span><a name="boost_regex.syntax.basic_syntax.posix_basic_syntax"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.posix_basic_syntax">POSIX
Basic Syntax</a>
</h4>
<p>
@ -52,9 +52,9 @@
for the following special characters:
</p>
<pre class="programlisting">.[\*^$</pre>
<a name="boost_regex.syntax.basic_syntax.wildcard_"></a><h5>
<a name="boost_regex.syntax.basic_syntax.wildcard_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.wildcard_">Wildcard:</a>
<h5>
<a name="boost_regex.syntax.basic_syntax.h2"></a>
<span><a name="boost_regex.syntax.basic_syntax.wildcard_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.wildcard_">Wildcard:</a>
</h5>
<p>
The single character '.' when used outside of a character set will match
@ -70,9 +70,9 @@
is passed to the matching algorithms.
</li>
</ul></div>
<a name="boost_regex.syntax.basic_syntax.anchors_"></a><h5>
<a name="boost_regex.syntax.basic_syntax.anchors_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.anchors_">Anchors:</a>
<h5>
<a name="boost_regex.syntax.basic_syntax.h3"></a>
<span><a name="boost_regex.syntax.basic_syntax.anchors_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.anchors_">Anchors:</a>
</h5>
<p>
A '^' character shall match the start of a line when used as the first character
@ -82,9 +82,9 @@
A '$' character shall match the end of a line when used as the last character
of an expression, or the last character of a sub-expression.
</p>
<a name="boost_regex.syntax.basic_syntax.marked_sub_expressions_"></a><h5>
<a name="boost_regex.syntax.basic_syntax.marked_sub_expressions_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.marked_sub_expressions_">Marked
<h5>
<a name="boost_regex.syntax.basic_syntax.h4"></a>
<span><a name="boost_regex.syntax.basic_syntax.marked_sub_expressions_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.marked_sub_expressions_">Marked
sub-expressions:</a>
</h5>
<p>
@ -94,9 +94,9 @@
matching algorithms. Marked sub-expressions can also repeated, or referred-to
by a back-reference.
</p>
<a name="boost_regex.syntax.basic_syntax.repeats_"></a><h5>
<a name="boost_regex.syntax.basic_syntax.repeats_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.repeats_">Repeats:</a>
<h5>
<a name="boost_regex.syntax.basic_syntax.h5"></a>
<span><a name="boost_regex.syntax.basic_syntax.repeats_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.repeats_">Repeats:</a>
</h5>
<p>
Any atom (a single character, a marked sub-expression, or a character class)
@ -152,9 +152,10 @@ aaaa
Will raise an error, as there is nothing for the * operator to be applied
to.
</p>
<a name="boost_regex.syntax.basic_syntax.back_references_"></a><h5>
<a name="boost_regex.syntax.basic_syntax.back_references_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.back_references_">Back references:</a>
<h5>
<a name="boost_regex.syntax.basic_syntax.h6"></a>
<span><a name="boost_regex.syntax.basic_syntax.back_references_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.back_references_">Back
references:</a>
</h5>
<p>
An escape character followed by a digit <span class="emphasis"><em>n</em></span>, where <span class="emphasis"><em>n</em></span>
@ -170,9 +171,9 @@ aaaa
But not the string:
</p>
<pre class="programlisting">aaabba</pre>
<a name="boost_regex.syntax.basic_syntax.character_sets_"></a><h5>
<a name="boost_regex.syntax.basic_syntax.character_sets_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.character_sets_">Character
<h5>
<a name="boost_regex.syntax.basic_syntax.h7"></a>
<span><a name="boost_regex.syntax.basic_syntax.character_sets_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.character_sets_">Character
sets:</a>
</h5>
<p>
@ -183,18 +184,18 @@ aaaa
<p>
A bracket expression may contain any combination of the following:
</p>
<a name="boost_regex.syntax.basic_syntax.single_characters_"></a><h6>
<a name="boost_regex.syntax.basic_syntax.single_characters_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.single_characters_">Single
<h6>
<a name="boost_regex.syntax.basic_syntax.h8"></a>
<span><a name="boost_regex.syntax.basic_syntax.single_characters_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.single_characters_">Single
characters:</a>
</h6>
<p>
For example <code class="computeroutput"><span class="special">[</span><span class="identifier">abc</span><span class="special">]</span></code>, will match any of the characters 'a', 'b',
or 'c'.
</p>
<a name="boost_regex.syntax.basic_syntax.character_ranges_"></a><h6>
<a name="boost_regex.syntax.basic_syntax.character_ranges_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.character_ranges_">Character
<h6>
<a name="boost_regex.syntax.basic_syntax.h9"></a>
<span><a name="boost_regex.syntax.basic_syntax.character_ranges_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.character_ranges_">Character
ranges:</a>
</h6>
<p>
@ -208,18 +209,18 @@ aaaa
a character appears within a range is determined by comparing the code points
of the characters only.
</p>
<a name="boost_regex.syntax.basic_syntax.negation_"></a><h6>
<a name="boost_regex.syntax.basic_syntax.negation_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.negation_">Negation:</a>
<h6>
<a name="boost_regex.syntax.basic_syntax.h10"></a>
<span><a name="boost_regex.syntax.basic_syntax.negation_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.negation_">Negation:</a>
</h6>
<p>
If the bracket-expression begins with the ^ character, then it matches the
complement of the characters it contains, for example <code class="computeroutput"><span class="special">[^</span><span class="identifier">a</span><span class="special">-</span><span class="identifier">c</span><span class="special">]</span></code> matches any character that is not in the
range a-c.
</p>
<a name="boost_regex.syntax.basic_syntax.character_classes_"></a><h6>
<a name="boost_regex.syntax.basic_syntax.character_classes_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.character_classes_">Character
<h6>
<a name="boost_regex.syntax.basic_syntax.h11"></a>
<span><a name="boost_regex.syntax.basic_syntax.character_classes_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.character_classes_">Character
classes:</a>
</h6>
<p>
@ -227,9 +228,9 @@ aaaa
matches the named character class "name", for example <code class="computeroutput"><span class="special">[[:</span><span class="identifier">lower</span><span class="special">:]]</span></code> matches any lower case character. See
<a class="link" href="character_classes.html" title="Character Class Names">character class names</a>.
</p>
<a name="boost_regex.syntax.basic_syntax.collating_elements_"></a><h6>
<a name="boost_regex.syntax.basic_syntax.collating_elements_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.collating_elements_">Collating
<h6>
<a name="boost_regex.syntax.basic_syntax.h12"></a>
<span><a name="boost_regex.syntax.basic_syntax.collating_elements_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.collating_elements_">Collating
Elements:</a>
</h6>
<p>
@ -256,9 +257,9 @@ aaaa
matches a 'NUL' character. See <a class="link" href="collating_names.html" title="Collating Names">collating
element names</a>.
</p>
<a name="boost_regex.syntax.basic_syntax.equivalence_classes_"></a><h6>
<a name="boost_regex.syntax.basic_syntax.equivalence_classes_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.equivalence_classes_">Equivalence
<h6>
<a name="boost_regex.syntax.basic_syntax.h13"></a>
<span><a name="boost_regex.syntax.basic_syntax.equivalence_classes_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.equivalence_classes_">Equivalence
classes:</a>
</h6>
<p>
@ -273,17 +274,17 @@ aaaa
this feature can not be relied upon to work portably across all platforms,
or even all locales on one platform.
</p>
<a name="boost_regex.syntax.basic_syntax.combinations_"></a><h6>
<a name="boost_regex.syntax.basic_syntax.combinations_-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.combinations_">Combinations:</a>
<h6>
<a name="boost_regex.syntax.basic_syntax.h14"></a>
<span><a name="boost_regex.syntax.basic_syntax.combinations_"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.combinations_">Combinations:</a>
</h6>
<p>
All of the above can be combined in one character set declaration, for example:
<code class="computeroutput"><span class="special">[[:</span><span class="identifier">digit</span><span class="special">:]</span><span class="identifier">a</span><span class="special">-</span><span class="identifier">c</span><span class="special">[.</span><span class="identifier">NUL</span><span class="special">.]].</span></code>
</p>
<a name="boost_regex.syntax.basic_syntax.escapes"></a><h5>
<a name="boost_regex.syntax.basic_syntax.escapes-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.escapes">Escapes</a>
<h5>
<a name="boost_regex.syntax.basic_syntax.h15"></a>
<span><a name="boost_regex.syntax.basic_syntax.escapes"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.escapes">Escapes</a>
</h5>
<p>
With the exception of the escape sequences \{, \}, \(, and \), which are
@ -296,23 +297,23 @@ aaaa
inside a character set, so <code class="computeroutput"><span class="special">[\^]</span></code>
will match either a literal '\' or a '^'.
</p>
<a name="boost_regex.syntax.basic_syntax.what_gets_matched"></a><h4>
<a name="boost_regex.syntax.basic_syntax.what_gets_matched-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.what_gets_matched">What Gets
Matched</a>
<h4>
<a name="boost_regex.syntax.basic_syntax.h16"></a>
<span><a name="boost_regex.syntax.basic_syntax.what_gets_matched"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.what_gets_matched">What
Gets Matched</a>
</h4>
<p>
When there is more that one way to match a regular expression, the "best"
possible match is obtained using the <a class="link" href="leftmost_longest_rule.html" title="The Leftmost Longest Rule">leftmost-longest
rule</a>.
</p>
<a name="boost_regex.syntax.basic_syntax.variations"></a><h4>
<a name="boost_regex.syntax.basic_syntax.variations-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.variations">Variations</a>
<h4>
<a name="boost_regex.syntax.basic_syntax.h17"></a>
<span><a name="boost_regex.syntax.basic_syntax.variations"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.variations">Variations</a>
</h4>
<a name="boost_regex.grep_syntax"></a><a name="boost_regex.syntax.basic_syntax.grep"></a><h5>
<a name="boost_regex.syntax.basic_syntax.grep-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.grep">Grep</a>
<a name="boost_regex.grep_syntax"></a><h5>
<a name="boost_regex.syntax.basic_syntax.h18"></a>
<span><a name="boost_regex.syntax.basic_syntax.grep"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.grep">Grep</a>
</h5>
<p>
When an expression is compiled with the flag <code class="computeroutput"><span class="identifier">grep</span></code>
@ -328,9 +329,9 @@ aaaa
<p>
As its name suggests, this behavior is consistent with the Unix utility grep.
</p>
<a name="boost_regex.syntax.basic_syntax.emacs"></a><h5>
<a name="boost_regex.syntax.basic_syntax.emacs-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.emacs">emacs</a>
<h5>
<a name="boost_regex.syntax.basic_syntax.h19"></a>
<span><a name="boost_regex.syntax.basic_syntax.emacs"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.emacs">emacs</a>
</h5>
<p>
In addition to the <a class="link" href="basic_syntax.html#boost_regex.posix_basic">POSIX-Basic features</a>
@ -608,9 +609,9 @@ aaaa
well with the <a class="link" href="leftmost_longest_rule.html" title="The Leftmost Longest Rule">POSIX-style
leftmost-longest rule</a>.
</p>
<a name="boost_regex.syntax.basic_syntax.options"></a><h4>
<a name="boost_regex.syntax.basic_syntax.options-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.options">Options</a>
<h4>
<a name="boost_regex.syntax.basic_syntax.h20"></a>
<span><a name="boost_regex.syntax.basic_syntax.options"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.options">Options</a>
</h4>
<p>
There are a <a class="link" href="../ref/syntax_option_type/syntax_option_type_basic.html" title="Options for POSIX Basic Regular Expressions">variety
@ -622,9 +623,9 @@ aaaa
all alter the syntax, while the <a class="link" href="../ref/syntax_option_type/syntax_option_type_basic.html" title="Options for POSIX Basic Regular Expressions"><code class="computeroutput"><span class="identifier">collate</span></code> and <code class="computeroutput"><span class="identifier">icase</span></code>
options</a> modify how the case and locale sensitivity are to be applied.
</p>
<a name="boost_regex.syntax.basic_syntax.references"></a><h4>
<a name="boost_regex.syntax.basic_syntax.references-heading"></a>
<a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.references">References</a>
<h4>
<a name="boost_regex.syntax.basic_syntax.h21"></a>
<span><a name="boost_regex.syntax.basic_syntax.references"></a></span><a class="link" href="basic_syntax.html#boost_regex.syntax.basic_syntax.references">References</a>
</h4>
<p>
<a href="http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap09.html" target="_top">IEEE

311
doc/html/boost_regex/syntax/perl_syntax.html
View File

@ -27,9 +27,9 @@
<a name="boost_regex.syntax.perl_syntax"></a><a class="link" href="perl_syntax.html" title="Perl Regular Expression Syntax">Perl Regular Expression
Syntax</a>
</h3></div></div></div>
<a name="boost_regex.syntax.perl_syntax.synopsis"></a><h4>
<a name="boost_regex.syntax.perl_syntax.synopsis-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.synopsis">Synopsis</a>
<h4>
<a name="boost_regex.syntax.perl_syntax.h0"></a>
<span><a name="boost_regex.syntax.perl_syntax.synopsis"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.synopsis">Synopsis</a>
</h4>
<p>
The Perl regular expression syntax is based on that used by the programming
@ -42,9 +42,9 @@
<span class="comment">// e2 a case insensitive Perl regular expression:</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span> <span class="identifier">e2</span><span class="special">(</span><span class="identifier">my_expression</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span><span class="special">::</span><span class="identifier">perl</span><span class="special">|</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span><span class="special">::</span><span class="identifier">icase</span><span class="special">);</span>
</pre>
<a name="boost_regex.syntax.perl_syntax.perl_regular_expression_syntax"></a><h4>
<a name="boost_regex.syntax.perl_syntax.perl_regular_expression_syntax-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.perl_regular_expression_syntax">Perl
<h4>
<a name="boost_regex.syntax.perl_syntax.h1"></a>
<span><a name="boost_regex.syntax.perl_syntax.perl_regular_expression_syntax"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.perl_regular_expression_syntax">Perl
Regular Expression Syntax</a>
</h4>
<p>
@ -52,9 +52,9 @@
following special characters:
</p>
<pre class="programlisting">.[{}()\*+?|^$</pre>
<a name="boost_regex.syntax.perl_syntax.wildcard"></a><h5>
<a name="boost_regex.syntax.perl_syntax.wildcard-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.wildcard">Wildcard</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h2"></a>
<span><a name="boost_regex.syntax.perl_syntax.wildcard"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.wildcard">Wildcard</a>
</h5>
<p>
The single character '.' when used outside of a character set will match
@ -72,9 +72,9 @@
algorithms.
</li>
</ul></div>
<a name="boost_regex.syntax.perl_syntax.anchors"></a><h5>
<a name="boost_regex.syntax.perl_syntax.anchors-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.anchors">Anchors</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h3"></a>
<span><a name="boost_regex.syntax.perl_syntax.anchors"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.anchors">Anchors</a>
</h5>
<p>
A '^' character shall match the start of a line.
@ -82,10 +82,9 @@
<p>
A '$' character shall match the end of a line.
</p>
<a name="boost_regex.syntax.perl_syntax.marked_sub_expressions"></a><h5>
<a name="boost_regex.syntax.perl_syntax.marked_sub_expressions-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.marked_sub_expressions">Marked
sub-expressions</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h4"></a>
<span><a name="boost_regex.syntax.perl_syntax.marked_sub_expressions"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.marked_sub_expressions">Marked sub-expressions</a>
</h5>
<p>
A section beginning <code class="literal">(</code> and ending <code class="literal">)</code>
@ -93,9 +92,9 @@
out in a separate field by the matching algorithms. Marked sub-expressions
can also repeated, or referred to by a back-reference.
</p>
<a name="boost_regex.syntax.perl_syntax.non_marking_grouping"></a><h5>
<a name="boost_regex.syntax.perl_syntax.non_marking_grouping-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.non_marking_grouping">Non-marking
<h5>
<a name="boost_regex.syntax.perl_syntax.h5"></a>
<span><a name="boost_regex.syntax.perl_syntax.non_marking_grouping"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.non_marking_grouping">Non-marking
grouping</a>
</h5>
<p>
@ -106,9 +105,9 @@
, for example <code class="literal">(?:ab)+</code> will repeat <code class="literal">ab</code>
without splitting out any separate sub-expressions.
</p>
<a name="boost_regex.syntax.perl_syntax.repeats"></a><h5>
<a name="boost_regex.syntax.perl_syntax.repeats-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.repeats">Repeats</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h6"></a>
<span><a name="boost_regex.syntax.perl_syntax.repeats"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.repeats">Repeats</a>
</h5>
<p>
Any atom (a single character, a marked sub-expression, or a character class)
@ -187,10 +186,10 @@
Will raise an error, as there is nothing for the <code class="literal">*</code> operator
to be applied to.
</p>
<a name="boost_regex.syntax.perl_syntax.non_greedy_repeats"></a><h5>
<a name="boost_regex.syntax.perl_syntax.non_greedy_repeats-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.non_greedy_repeats">Non greedy
repeats</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h7"></a>
<span><a name="boost_regex.syntax.perl_syntax.non_greedy_repeats"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.non_greedy_repeats">Non
greedy repeats</a>
</h5>
<p>
The normal repeat operators are "greedy", that is to say they will
@ -217,9 +216,9 @@
<code class="literal">{n,m}?</code> Matches the previous atom between n and m times,
while consuming as little input as possible.
</p>
<a name="boost_regex.syntax.perl_syntax.possessive_repeats"></a><h5>
<a name="boost_regex.syntax.perl_syntax.possessive_repeats-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.possessive_repeats">Possessive
<h5>
<a name="boost_regex.syntax.perl_syntax.h8"></a>
<span><a name="boost_regex.syntax.perl_syntax.possessive_repeats"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.possessive_repeats">Possessive
repeats</a>
</h5>
<p>
@ -249,9 +248,10 @@
<code class="literal">{n,m}+</code> Matches the previous atom between n and m times,
while giving nothing back.
</p>
<a name="boost_regex.syntax.perl_syntax.back_references"></a><h5>
<a name="boost_regex.syntax.perl_syntax.back_references-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.back_references">Back references</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h9"></a>
<span><a name="boost_regex.syntax.perl_syntax.back_references"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.back_references">Back
references</a>
</h5>
<p>
An escape character followed by a digit <span class="emphasis"><em>n</em></span>, where <span class="emphasis"><em>n</em></span>
@ -359,9 +359,9 @@
<code class="literal">\k&lt;two&gt;</code> will match whatever matched the subexpression
named "two".
</p>
<a name="boost_regex.syntax.perl_syntax.alternation"></a><h5>
<a name="boost_regex.syntax.perl_syntax.alternation-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.alternation">Alternation</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h10"></a>
<span><a name="boost_regex.syntax.perl_syntax.alternation"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.alternation">Alternation</a>
</h5>
<p>
The <code class="literal">|</code> operator will match either of its arguments, so
@ -386,9 +386,10 @@
<p>
<code class="literal">(?:abc)??</code> has exactly the same effect.
</p>
<a name="boost_regex.syntax.perl_syntax.character_sets"></a><h5>
<a name="boost_regex.syntax.perl_syntax.character_sets-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.character_sets">Character sets</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h11"></a>
<span><a name="boost_regex.syntax.perl_syntax.character_sets"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.character_sets">Character
sets</a>
</h5>
<p>
A character set is a bracket-expression starting with <code class="literal">[</code>
@ -398,16 +399,17 @@
<p>
A bracket expression may contain any combination of the following:
</p>
<a name="boost_regex.syntax.perl_syntax.single_characters"></a><h6>
<a name="boost_regex.syntax.perl_syntax.single_characters-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.single_characters">Single characters</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h12"></a>
<span><a name="boost_regex.syntax.perl_syntax.single_characters"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.single_characters">Single
characters</a>
</h6>
<p>
For example =[abc]=, will match any of the characters 'a', 'b', or 'c'.
</p>
<a name="boost_regex.syntax.perl_syntax.character_ranges"></a><h6>
<a name="boost_regex.syntax.perl_syntax.character_ranges-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.character_ranges">Character
<h6>
<a name="boost_regex.syntax.perl_syntax.h13"></a>
<span><a name="boost_regex.syntax.perl_syntax.character_ranges"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.character_ranges">Character
ranges</a>
</h6>
<p>
@ -418,18 +420,18 @@
flag</a> when constructing the regular expression, then ranges are locale
sensitive.
</p>
<a name="boost_regex.syntax.perl_syntax.negation"></a><h6>
<a name="boost_regex.syntax.perl_syntax.negation-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.negation">Negation</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h14"></a>
<span><a name="boost_regex.syntax.perl_syntax.negation"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.negation">Negation</a>
</h6>
<p>
If the bracket-expression begins with the ^ character, then it matches the
complement of the characters it contains, for example =<code class="literal">a-c</code>=
matches any character that is not in the range <code class="literal">a-c</code>.
</p>
<a name="boost_regex.syntax.perl_syntax.character_classes"></a><h6>
<a name="boost_regex.syntax.perl_syntax.character_classes-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.character_classes">Character
<h6>
<a name="boost_regex.syntax.perl_syntax.h15"></a>
<span><a name="boost_regex.syntax.perl_syntax.character_classes"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.character_classes">Character
classes</a>
</h6>
<p>
@ -438,9 +440,9 @@
matches any lower case character. See <a class="link" href="character_classes.html" title="Character Class Names">character
class names</a>.
</p>
<a name="boost_regex.syntax.perl_syntax.collating_elements"></a><h6>
<a name="boost_regex.syntax.perl_syntax.collating_elements-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.collating_elements">Collating
<h6>
<a name="boost_regex.syntax.perl_syntax.h16"></a>
<span><a name="boost_regex.syntax.perl_syntax.collating_elements"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.collating_elements">Collating
Elements</a>
</h6>
<p>
@ -460,9 +462,9 @@
<p>
matches a <code class="literal">\0</code> character.
</p>
<a name="boost_regex.syntax.perl_syntax.equivalence_classes"></a><h6>
<a name="boost_regex.syntax.perl_syntax.equivalence_classes-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.equivalence_classes">Equivalence
<h6>
<a name="boost_regex.syntax.perl_syntax.h17"></a>
<span><a name="boost_regex.syntax.perl_syntax.equivalence_classes"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.equivalence_classes">Equivalence
classes</a>
</h6>
<p>
@ -477,9 +479,9 @@
this feature can not be relied upon to work portably across all platforms,
or even all locales on one platform.
</p>
<a name="boost_regex.syntax.perl_syntax.escaped_characters"></a><h6>
<a name="boost_regex.syntax.perl_syntax.escaped_characters-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.escaped_characters">Escaped
<h6>
<a name="boost_regex.syntax.perl_syntax.h18"></a>
<span><a name="boost_regex.syntax.perl_syntax.escaped_characters"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.escaped_characters">Escaped
Characters</a>
</h6>
<p>
@ -489,17 +491,17 @@
would match any character that is either a "digit", <span class="emphasis"><em>or</em></span>
is <span class="emphasis"><em>not</em></span> a "word" character.
</p>
<a name="boost_regex.syntax.perl_syntax.combinations"></a><h6>
<a name="boost_regex.syntax.perl_syntax.combinations-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.combinations">Combinations</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h19"></a>
<span><a name="boost_regex.syntax.perl_syntax.combinations"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.combinations">Combinations</a>
</h6>
<p>
All of the above can be combined in one character set declaration, for example:
<code class="literal">[[:digit:]a-c[.NUL.]]</code>.
</p>
<a name="boost_regex.syntax.perl_syntax.escapes"></a><h5>
<a name="boost_regex.syntax.perl_syntax.escapes-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.escapes">Escapes</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h20"></a>
<span><a name="boost_regex.syntax.perl_syntax.escapes"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.escapes">Escapes</a>
</h5>
<p>
Any special character preceded by an escape shall match itself.
@ -689,9 +691,9 @@
</tr>
</tbody>
</table></div>
<a name="boost_regex.syntax.perl_syntax._quot_single_character_quot__character_classes_"></a><h6>
<a name="boost_regex.syntax.perl_syntax._quot_single_character_quot__character_classes_-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax._quot_single_character_quot__character_classes_">"Single
<h6>
<a name="boost_regex.syntax.perl_syntax.h21"></a>
<span><a name="boost_regex.syntax.perl_syntax._quot_single_character_quot__character_classes_"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax._quot_single_character_quot__character_classes_">"Single
character" character classes:</a>
</h6>
<p>
@ -891,9 +893,9 @@
</tr>
</tbody>
</table></div>
<a name="boost_regex.syntax.perl_syntax.character_properties"></a><h6>
<a name="boost_regex.syntax.perl_syntax.character_properties-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.character_properties">Character
<h6>
<a name="boost_regex.syntax.perl_syntax.h22"></a>
<span><a name="boost_regex.syntax.perl_syntax.character_properties"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.character_properties">Character
Properties</a>
</h6>
<p>
@ -999,9 +1001,10 @@
For example <code class="literal">\pd</code> matches any "digit" character,
as does <code class="literal">\p{digit}</code>.
</p>
<a name="boost_regex.syntax.perl_syntax.word_boundaries"></a><h6>
<a name="boost_regex.syntax.perl_syntax.word_boundaries-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.word_boundaries">Word Boundaries</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h23"></a>
<span><a name="boost_regex.syntax.perl_syntax.word_boundaries"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.word_boundaries">Word
Boundaries</a>
</h6>
<p>
The following escape sequences match the boundaries of words:
@ -1018,9 +1021,10 @@
<p>
<code class="literal">\B</code> Matches only when not at a word boundary.
</p>
<a name="boost_regex.syntax.perl_syntax.buffer_boundaries"></a><h6>
<a name="boost_regex.syntax.perl_syntax.buffer_boundaries-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.buffer_boundaries">Buffer boundaries</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h24"></a>
<span><a name="boost_regex.syntax.perl_syntax.buffer_boundaries"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.buffer_boundaries">Buffer
boundaries</a>
</h6>
<p>
The following match only at buffer boundaries: a "buffer" in this
@ -1045,9 +1049,9 @@
Note that this is subtly different from Perl which behaves as if matching
<code class="literal">(?=\n?\z)</code>.
</p>
<a name="boost_regex.syntax.perl_syntax.continuation_escape"></a><h6>
<a name="boost_regex.syntax.perl_syntax.continuation_escape-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.continuation_escape">Continuation
<h6>
<a name="boost_regex.syntax.perl_syntax.h25"></a>
<span><a name="boost_regex.syntax.perl_syntax.continuation_escape"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.continuation_escape">Continuation
Escape</a>
</h6>
<p>
@ -1057,9 +1061,10 @@
within a text, and you want each subsequence match to start where the last
one ended.
</p>
<a name="boost_regex.syntax.perl_syntax.quoting_escape"></a><h6>
<a name="boost_regex.syntax.perl_syntax.quoting_escape-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.quoting_escape">Quoting escape</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h26"></a>
<span><a name="boost_regex.syntax.perl_syntax.quoting_escape"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.quoting_escape">Quoting
escape</a>
</h6>
<p>
The escape sequence <code class="literal">\Q</code> begins a "quoted sequence":
@ -1070,9 +1075,10 @@
<pre class="programlisting"><span class="special">\*+</span><span class="identifier">a</span>
<span class="special">\*+</span><span class="identifier">aaa</span>
</pre>
<a name="boost_regex.syntax.perl_syntax.unicode_escapes"></a><h6>
<a name="boost_regex.syntax.perl_syntax.unicode_escapes-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.unicode_escapes">Unicode escapes</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h27"></a>
<span><a name="boost_regex.syntax.perl_syntax.unicode_escapes"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.unicode_escapes">Unicode
escapes</a>
</h6>
<p>
<code class="literal">\C</code> Matches a single code point: in Boost regex this has
@ -1080,19 +1086,19 @@
Matches a combining character sequence: that is any non-combining character
followed by a sequence of zero or more combining characters.
</p>
<a name="boost_regex.syntax.perl_syntax.matching_line_endings"></a><h6>
<a name="boost_regex.syntax.perl_syntax.matching_line_endings-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.matching_line_endings">Matching
Line Endings</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h28"></a>
<span><a name="boost_regex.syntax.perl_syntax.matching_line_endings"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.matching_line_endings">Matching Line
Endings</a>
</h6>
<p>
The escape sequence <code class="literal">\R</code> matches any line ending character
sequence, specifically it is identical to the expression <code class="literal">(?&gt;\x0D\x0A?|[\x0A-\x0C\x85\x{2028}\x{2029}])</code>.
</p>
<a name="boost_regex.syntax.perl_syntax.keeping_back_some_text"></a><h6>
<a name="boost_regex.syntax.perl_syntax.keeping_back_some_text-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.keeping_back_some_text">Keeping
back some text</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h29"></a>
<span><a name="boost_regex.syntax.perl_syntax.keeping_back_some_text"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.keeping_back_some_text">Keeping back
some text</a>
</h6>
<p>
<code class="literal">\K</code> Resets the start location of $0 to the current text
@ -1104,27 +1110,27 @@
would return the match "bar" for $0 and "foo" for $`.
This can be used to simulate variable width lookbehind assertions.
</p>
<a name="boost_regex.syntax.perl_syntax.any_other_escape"></a><h6>
<a name="boost_regex.syntax.perl_syntax.any_other_escape-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.any_other_escape">Any other
escape</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h30"></a>
<span><a name="boost_regex.syntax.perl_syntax.any_other_escape"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.any_other_escape">Any
other escape</a>
</h6>
<p>
Any other escape sequence matches the character that is escaped, for example
\@ matches a literal '@'.
</p>
<a name="boost_regex.syntax.perl_syntax.perl_extended_patterns"></a><h5>
<a name="boost_regex.syntax.perl_syntax.perl_extended_patterns-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.perl_extended_patterns">Perl
Extended Patterns</a>
<h5>
<a name="boost_regex.syntax.perl_syntax.h31"></a>
<span><a name="boost_regex.syntax.perl_syntax.perl_extended_patterns"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.perl_extended_patterns">Perl Extended
Patterns</a>
</h5>
<p>
Perl-specific extensions to the regular expression syntax all start with
<code class="literal">(?</code>.
</p>
<a name="boost_regex.syntax.perl_syntax.named_subexpressions"></a><h6>
<a name="boost_regex.syntax.perl_syntax.named_subexpressions-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.named_subexpressions">Named
<h6>
<a name="boost_regex.syntax.perl_syntax.h32"></a>
<span><a name="boost_regex.syntax.perl_syntax.named_subexpressions"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.named_subexpressions">Named
Subexpressions</a>
</h6>
<p>
@ -1144,16 +1150,16 @@
also be refered to by name in a <a class="link" href="../format/perl_format.html" title="Perl Format String Syntax">Perl</a>
format string for search and replace operations, or in the <a class="link" href="../ref/match_results.html" title="match_results"><code class="computeroutput"><span class="identifier">match_results</span></code></a> member functions.
</p>
<a name="boost_regex.syntax.perl_syntax.comments"></a><h6>
<a name="boost_regex.syntax.perl_syntax.comments-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.comments">Comments</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h33"></a>
<span><a name="boost_regex.syntax.perl_syntax.comments"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.comments">Comments</a>
</h6>
<p>
<code class="literal">(?# ... )</code> is treated as a comment, it's contents are ignored.
</p>
<a name="boost_regex.syntax.perl_syntax.modifiers"></a><h6>
<a name="boost_regex.syntax.perl_syntax.modifiers-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.modifiers">Modifiers</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h34"></a>
<span><a name="boost_regex.syntax.perl_syntax.modifiers"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.modifiers">Modifiers</a>
</h6>
<p>
<code class="literal">(?imsx-imsx ... )</code> alters which of the perl modifiers are
@ -1165,18 +1171,19 @@
<code class="literal">(?imsx-imsx:pattern)</code> applies the specified modifiers to
pattern only.
</p>
<a name="boost_regex.syntax.perl_syntax.non_marking_groups"></a><h6>
<a name="boost_regex.syntax.perl_syntax.non_marking_groups-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.non_marking_groups">Non-marking
<h6>
<a name="boost_regex.syntax.perl_syntax.h35"></a>
<span><a name="boost_regex.syntax.perl_syntax.non_marking_groups"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.non_marking_groups">Non-marking
groups</a>
</h6>
<p>
<code class="literal">(?:pattern)</code> lexically groups pattern, without generating
an additional sub-expression.
</p>
<a name="boost_regex.syntax.perl_syntax.branch_reset"></a><h6>
<a name="boost_regex.syntax.perl_syntax.branch_reset-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.branch_reset">Branch reset</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h36"></a>
<span><a name="boost_regex.syntax.perl_syntax.branch_reset"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.branch_reset">Branch
reset</a>
</h6>
<p>
<code class="literal">(?|pattern)</code> resets the subexpression count at the start
@ -1192,13 +1199,13 @@
In the following example the index of each sub-expression is shown below
the expression:
</p>
<pre class="programlisting"># before ---------------branch-reset----------- after
<pre class="programlisting"># before ---------------branch-reset----------- after
/ ( a ) (?| x ( y ) z | (p (q) r) | (t) u (v) ) ( z ) /x
# 1 2 2 3 2 3 4
</pre>
<a name="boost_regex.syntax.perl_syntax.lookahead"></a><h6>
<a name="boost_regex.syntax.perl_syntax.lookahead-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.lookahead">Lookahead</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h37"></a>
<span><a name="boost_regex.syntax.perl_syntax.lookahead"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.lookahead">Lookahead</a>
</h6>
<p>
<code class="literal">(?=pattern)</code> consumes zero characters, only if pattern
@ -1219,9 +1226,9 @@
<p>
could be used to validate the password.
</p>
<a name="boost_regex.syntax.perl_syntax.lookbehind"></a><h6>
<a name="boost_regex.syntax.perl_syntax.lookbehind-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.lookbehind">Lookbehind</a>
<h6>
<a name="boost_regex.syntax.perl_syntax.h38"></a>
<span><a name="boost_regex.syntax.perl_syntax.lookbehind"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.lookbehind">Lookbehind</a>
</h6>
<p>
<code class="literal">(?&lt;=pattern)</code> consumes zero characters, only if pattern
@ -1233,9 +1240,9 @@
could not be matched against the characters preceding the current position
(pattern must be of fixed length).
</p>
<a name="boost_regex.syntax.perl_syntax.independent_sub_expressions"></a><h6>
<a name="boost_regex.syntax.perl_syntax.independent_sub_expressions-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.independent_sub_expressions">Independent
<h6>
<a name="boost_regex.syntax.perl_syntax.h39"></a>
<span><a name="boost_regex.syntax.perl_syntax.independent_sub_expressions"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.independent_sub_expressions">Independent
sub-expressions</a>
</h6>
<p>
@ -1246,9 +1253,9 @@
be considered, if this doesn't allow the expression as a whole to match then
no match is found at all.
</p>
<a name="boost_regex.syntax.perl_syntax.recursive_expressions"></a><h6>
<a name="boost_regex.syntax.perl_syntax.recursive_expressions-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.recursive_expressions">Recursive
<h6>
<a name="boost_regex.syntax.perl_syntax.h40"></a>
<span><a name="boost_regex.syntax.perl_syntax.recursive_expressions"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.recursive_expressions">Recursive
Expressions</a>
</h6>
<p>
@ -1273,9 +1280,9 @@
<p>
<code class="literal">(?&amp;NAME)</code> recurses to named sub-expression <span class="emphasis"><em>NAME</em></span>.
</p>
<a name="boost_regex.syntax.perl_syntax.conditional_expressions"></a><h6>
<a name="boost_regex.syntax.perl_syntax.conditional_expressions-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.conditional_expressions">Conditional
<h6>
<a name="boost_regex.syntax.perl_syntax.h41"></a>
<span><a name="boost_regex.syntax.perl_syntax.conditional_expressions"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.conditional_expressions">Conditional
Expressions</a>
</h6>
<p>
@ -1323,9 +1330,9 @@
from elsewhere in the pattern.
</li>
</ul></div>
<a name="boost_regex.syntax.perl_syntax.operator_precedence"></a><h5>
<a name="boost_regex.syntax.perl_syntax.operator_precedence-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.operator_precedence">Operator
<h5>
<a name="boost_regex.syntax.perl_syntax.h42"></a>
<span><a name="boost_regex.syntax.perl_syntax.operator_precedence"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.operator_precedence">Operator
precedence</a>
</h5>
<p>
@ -1358,10 +1365,10 @@
Alternation |
</li>
</ol></div>
<a name="boost_regex.syntax.perl_syntax.what_gets_matched"></a><h4>
<a name="boost_regex.syntax.perl_syntax.what_gets_matched-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.what_gets_matched">What gets
matched</a>
<h4>
<a name="boost_regex.syntax.perl_syntax.h43"></a>
<span><a name="boost_regex.syntax.perl_syntax.what_gets_matched"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.what_gets_matched">What
gets matched</a>
</h4>
<p>
If you view the regular expression as a directed (possibly cyclic) graph,
@ -1534,18 +1541,18 @@
</tr>
</tbody>
</table></div>
<a name="boost_regex.syntax.perl_syntax.variations"></a><h4>
<a name="boost_regex.syntax.perl_syntax.variations-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.variations">Variations</a>
<h4>
<a name="boost_regex.syntax.perl_syntax.h44"></a>
<span><a name="boost_regex.syntax.perl_syntax.variations"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.variations">Variations</a>
</h4>
<p>
The <a class="link" href="../ref/syntax_option_type/syntax_option_type_perl.html" title="Options for Perl Regular Expressions">options
<code class="literal">normal</code>, <code class="literal">ECMAScript</code>, <code class="literal">JavaScript</code>
and <code class="literal">JScript</code></a> are all synonyms for <code class="literal">perl</code>.
</p>
<a name="boost_regex.syntax.perl_syntax.options"></a><h4>
<a name="boost_regex.syntax.perl_syntax.options-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.options">Options</a>
<h4>
<a name="boost_regex.syntax.perl_syntax.h45"></a>
<span><a name="boost_regex.syntax.perl_syntax.options"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.options">Options</a>
</h4>
<p>
There are a <a class="link" href="../ref/syntax_option_type/syntax_option_type_perl.html" title="Options for Perl Regular Expressions">variety
@ -1555,9 +1562,9 @@
and <code class="literal">icase</code> options modify how the case and locale sensitivity
are to be applied.
</p>
<a name="boost_regex.syntax.perl_syntax.pattern_modifiers"></a><h4>
<a name="boost_regex.syntax.perl_syntax.pattern_modifiers-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.pattern_modifiers">Pattern
<h4>
<a name="boost_regex.syntax.perl_syntax.h46"></a>
<span><a name="boost_regex.syntax.perl_syntax.pattern_modifiers"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.pattern_modifiers">Pattern
Modifiers</a>
</h4>
<p>
@ -1567,9 +1574,9 @@
time flags <code class="literal">no_mod_m</code>, <code class="literal">mod_x</code>, <code class="literal">mod_s</code>,
and <code class="literal">no_mod_s</code></a>.
</p>
<a name="boost_regex.syntax.perl_syntax.references"></a><h4>
<a name="boost_regex.syntax.perl_syntax.references-heading"></a>
<a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.references">References</a>
<h4>
<a name="boost_regex.syntax.perl_syntax.h47"></a>
<span><a name="boost_regex.syntax.perl_syntax.references"></a></span><a class="link" href="perl_syntax.html#boost_regex.syntax.perl_syntax.references">References</a>
</h4>
<p>
<a href="http://perldoc.perl.org/perlre.html" target="_top">Perl 5.8</a>.