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| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="boost_regex.ref.syntax_option_type.syntax_option_type_extended"></a><a class="link" href="syntax_option_type_extended.html" title="Options for POSIX Extended Regular Expressions"> |
| Options for POSIX Extended Regular Expressions</a> |
| </h4></div></div></div> |
| <p> |
| Exactly one of the following must always be set for <a class="link" href="../../syntax/basic_extended.html" title="POSIX Extended Regular Expression Syntax">POSIX |
| extended regular expressions</a>: |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Element |
| </p> |
| </th> |
| <th> |
| <p> |
| Standardized |
| </p> |
| </th> |
| <th> |
| <p> |
| Effect when set |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| extended |
| </p> |
| </td> |
| <td> |
| <p> |
| Yes |
| </p> |
| </td> |
| <td> |
| <p> |
| Specifies that the grammar recognized by the regular expression |
| engine is the same as that used by POSIX extended regular expressions |
| in IEEE Std 1003.1-2001, Portable Operating System Interface |
| (POSIX ), Base Definitions and Headers, Section 9, Regular Expressions |
| (FWD.1). |
| </p> |
| <p> |
| Refer to the <a class="link" href="../../syntax/basic_extended.html" title="POSIX Extended Regular Expression Syntax">POSIX |
| extended regular expression guide</a> for more information. |
| </p> |
| <p> |
| In addition some perl-style escape sequences are supported (The |
| POSIX standard specifies that only "special" characters |
| may be escaped, all other escape sequences result in undefined |
| behavior). |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| egrep |
| </p> |
| </td> |
| <td> |
| <p> |
| Yes |
| </p> |
| </td> |
| <td> |
| <p> |
| Specifies that the grammar recognized by the regular expression |
| engine is the same as that used by POSIX utility grep when given |
| the -E option in IEEE Std 1003.1-2001, Portable Operating System |
| Interface (POSIX ), Shells and Utilities, Section 4, Utilities, |
| grep (FWD.1). |
| </p> |
| <p> |
| That is to say, the same as <a class="link" href="../../syntax/basic_extended.html" title="POSIX Extended Regular Expression Syntax">POSIX |
| extended syntax</a>, but with the newline character acting |
| as an alternation character in addition to "|". |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| awk |
| </p> |
| </td> |
| <td> |
| <p> |
| Yes |
| </p> |
| </td> |
| <td> |
| <p> |
| Specifies that the grammar recognized by the regular expression |
| engine is the same as that used by POSIX utility awk in IEEE |
| Std 1003.1-2001, Portable Operating System Interface (POSIX ), |
| Shells and Utilities, Section 4, awk (FWD.1). |
| </p> |
| <p> |
| That is to say: the same as <a class="link" href="../../syntax/basic_extended.html" title="POSIX Extended Regular Expression Syntax">POSIX |
| extended syntax</a>, but with escape sequences in character |
| classes permitted. |
| </p> |
| <p> |
| In addition some perl-style escape sequences are supported (actually |
| the awk syntax only requires \a \b \t \v \f \n and \r to be recognised, |
| all other Perl-style escape sequences invoke undefined behavior |
| according to the POSIX standard, but are in fact recognised by |
| Boost.Regex). |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <p> |
| The following options may also be set when using POSIX extended regular |
| expressions: |
| </p> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Element |
| </p> |
| </th> |
| <th> |
| <p> |
| Standardized |
| </p> |
| </th> |
| <th> |
| <p> |
| Effect when set |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| icase |
| </p> |
| </td> |
| <td> |
| <p> |
| Yes |
| </p> |
| </td> |
| <td> |
| <p> |
| Specifies that matching of regular expressions against a character |
| container sequence shall be performed without regard to case. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| nosubs |
| </p> |
| </td> |
| <td> |
| <p> |
| Yes |
| </p> |
| </td> |
| <td> |
| <p> |
| Specifies that when a regular expression is matched against a |
| character container sequence, then no sub-expression matches |
| are to be stored in the supplied <a class="link" href="../match_results.html" title="match_results"><code class="computeroutput"><span class="identifier">match_results</span></code></a> structure. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| optimize |
| </p> |
| </td> |
| <td> |
| <p> |
| Yes |
| </p> |
| </td> |
| <td> |
| <p> |
| Specifies that the regular expression engine should pay more |
| attention to the speed with which regular expressions are matched, |
| and less to the speed with which regular expression objects are |
| constructed. Otherwise it has no detectable effect on the program |
| output. This currently has no effect for Boost.Regex. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| collate |
| </p> |
| </td> |
| <td> |
| <p> |
| Yes |
| </p> |
| </td> |
| <td> |
| <p> |
| Specifies that character ranges of the form <code class="computeroutput"><span class="special">[</span><span class="identifier">a</span><span class="special">-</span><span class="identifier">b</span><span class="special">]</span></code> |
| should be locale sensitive. This bit is on by default for POSIX-Extended |
| regular expressions, but can be unset to force ranges to be compared |
| by code point only. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| newline_alt |
| </p> |
| </td> |
| <td> |
| <p> |
| No |
| </p> |
| </td> |
| <td> |
| <p> |
| Specifies that the \n character has the same effect as the alternation |
| operator |. Allows newline separated lists to be used as a list |
| of alternatives. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| no_escape_in_lists |
| </p> |
| </td> |
| <td> |
| <p> |
| No |
| </p> |
| </td> |
| <td> |
| <p> |
| When set this makes the escape character ordinary inside lists, |
| so that <code class="computeroutput"><span class="special">[\</span><span class="identifier">b</span><span class="special">]</span></code> would match either '\' or 'b'. |
| This bit is on by default for POSIX-Extended regular expressions, |
| but can be unset to force escapes to be recognised inside lists. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| no_bk_refs |
| </p> |
| </td> |
| <td> |
| <p> |
| No |
| </p> |
| </td> |
| <td> |
| <p> |
| When set then backreferences are disabled. This bit is on by |
| default for POSIX-Extended regular expressions, but can be unset |
| to support for backreferences on. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| no_except |
| </p> |
| </td> |
| <td> |
| <p> |
| No |
| </p> |
| </td> |
| <td> |
| <p> |
| Prevents <a class="link" href="../basic_regex.html" title="basic_regex"><code class="computeroutput"><span class="identifier">basic_regex</span></code></a> from throwing |
| an exception when an invalid expression is encountered. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| save_subexpression_location |
| </p> |
| </td> |
| <td> |
| <p> |
| No |
| </p> |
| </td> |
| <td> |
| <p> |
| When set then the locations of individual sub-expressions within |
| the <span class="emphasis"><em>original regular expression string</em></span> can |
| be accessed via the <a class="link" href="../basic_regex.html#boost_regex.basic_regex.subexpression"><code class="computeroutput"><span class="identifier">subexpression</span><span class="special">()</span></code></a> |
| member function of <code class="computeroutput"><span class="identifier">basic_regex</span></code>. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 1998 -2010 John Maddock<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
| </p> |
| </div></td> |
| </tr></table> |
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