PCRE2Project/pcre2
1
0
Fork 0
mirror of https://github.com/PCRE2Project/pcre2.git synced 2025-10-20 04:25:35 +08:00
Code Issues Packages Projects Releases Wiki Activity

Update HTML and plain text documentation

Browse Source
This commit is contained in:
Philip Hazel
2023-08-11 19:09:17 +01:00
parent 5974a84364
commit 8314be909f
8 changed files with 989 additions and 972 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
doc/html/pcre2compat.html
View File

@@ -16,10 +16,10 @@ please consult the man page, in case the conversion went wrong.
DIFFERENCES BETWEEN PCRE2 AND PERL
</b><br>
<P>
This document describes some of the differences in the ways that PCRE2 and Perl
handle regular expressions. The differences described here are with respect to
Perl version 5.34.0, but as both Perl and PCRE2 are continually changing, the
information may at times be out of date.
This document describes some of the known differences in the ways that PCRE2
and Perl handle regular expressions. The differences described here are with
respect to Perl version 5.34.0, but as both Perl and PCRE2 are continually
changing, the information may at times be out of date.
</P>
<P>
1. When PCRE2_DOTALL (equivalent to Perl's /s qualifier) is not set, the
@@ -173,59 +173,48 @@ of which (such as named parentheses) were in PCRE2 for some time before. This
list is with respect to Perl 5.34:
<br>
<br>
(a) Although lookbehind assertions in PCRE2 must match fixed length strings,
each alternative toplevel branch of a lookbehind assertion can match a
different length of string. Perl used to require them all to have the same
length, but the latest version has some variable length support.
<br>
<br>
(b) From PCRE2 10.23, backreferences to groups of fixed length are supported
in lookbehinds, provided that there is no possibility of referencing a
non-unique number or name. Perl does not support backreferences in lookbehinds.
<br>
<br>
(c) If PCRE2_DOLLAR_ENDONLY is set and PCRE2_MULTILINE is not set, the $
(a) If PCRE2_DOLLAR_ENDONLY is set and PCRE2_MULTILINE is not set, the $
meta-character matches only at the very end of the string.
<br>
<br>
(d) A backslash followed by a letter with no special meaning is faulted. (Perl
(b) A backslash followed by a letter with no special meaning is faulted. (Perl
can be made to issue a warning.)
<br>
<br>
(e) If PCRE2_UNGREEDY is set, the greediness of the repetition quantifiers is
(c) If PCRE2_UNGREEDY is set, the greediness of the repetition quantifiers is
inverted, that is, by default they are not greedy, but if followed by a
question mark they are.
<br>
<br>
(f) PCRE2_ANCHORED can be used at matching time to force a pattern to be tried
(d) PCRE2_ANCHORED can be used at matching time to force a pattern to be tried
only at the first matching position in the subject string.
<br>
<br>
(g) The PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY and PCRE2_NOTEMPTY_ATSTART
(e) The PCRE2_NOTBOL, PCRE2_NOTEOL, PCRE2_NOTEMPTY and PCRE2_NOTEMPTY_ATSTART
options have no Perl equivalents.
<br>
<br>
(h) The \R escape sequence can be restricted to match only CR, LF, or CRLF
(f) The \R escape sequence can be restricted to match only CR, LF, or CRLF
by the PCRE2_BSR_ANYCRLF option.
<br>
<br>
(i) The callout facility is PCRE2-specific. Perl supports codeblocks and
(g) The callout facility is PCRE2-specific. Perl supports codeblocks and
variable interpolation, but not general hooks on every match.
<br>
<br>
(j) The partial matching facility is PCRE2-specific.
(h) The partial matching facility is PCRE2-specific.
<br>
<br>
(k) The alternative matching function (<b>pcre2_dfa_match()</b> matches in a
(i) The alternative matching function (<b>pcre2_dfa_match()</b> matches in a
different way and is not Perl-compatible.
<br>
<br>
(l) PCRE2 recognizes some special sequences such as (*CR) or (*NO_JIT) at
(j) PCRE2 recognizes some special sequences such as (*CR) or (*NO_JIT) at
the start of a pattern. These set overall options that cannot be changed within
the pattern.
<br>
<br>
(m) PCRE2 supports non-atomic positive lookaround assertions. This is an
(k) PCRE2 supports non-atomic positive lookaround assertions. This is an
extension to the lookaround facilities. The default, Perl-compatible
lookarounds are atomic.
</P>
@@ -252,7 +241,7 @@ Cambridge, England.
REVISION
</b><br>
<P>
Last updated: 03 February 2023
Last updated: 11 August 2023
<br>
Copyright &copy; 1997-2023 University of Cambridge.
<br>