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Diffstat (limited to 'doc/pcre.3')
| -rw-r--r-- | doc/pcre.3 | 31 |
1 files changed, 17 insertions, 14 deletions
@@ -6,12 +6,16 @@ PCRE - Perl-compatible regular expressions .sp The PCRE library is a set of functions that implement regular expression pattern matching using the same syntax and semantics as Perl, with just a few -differences. The current implementation of PCRE (release 6.x) corresponds -approximately with Perl 5.8, including support for UTF-8 encoded strings and -Unicode general category properties. However, this support has to be explicitly -enabled; it is not the default. +differences. (Certain features that appeared in Python and PCRE before they +appeared in Perl are also available using the Python syntax.) .P -In addition to the Perl-compatible matching function, PCRE also contains an +The current implementation of PCRE (release 7.x) corresponds approximately with +Perl 5.10, including support for UTF-8 encoded strings and Unicode general +category properties. However, UTF-8 and Unicode support has to be explicitly +enabled; it is not the default. The Unicode tables correspond to Unicode +release 5.0.0. +.P +In addition to the Perl-compatible matching function, PCRE contains an alternative matching function that matches the same compiled patterns in a different way. In certain circumstances, the alternative function has some advantages. For a discussion of the two matching algorithms, see the @@ -114,18 +118,17 @@ distribution and the \fBpcrebuild\fP .\" documentation for details). In these cases the limit is substantially larger. -However, the speed of execution will be slower. +However, the speed of execution is slower. .P All values in repeating quantifiers must be less than 65536. The maximum compiled length of subpattern with an explicit repeat count is 30000 bytes. The maximum number of capturing subpatterns is 65535. .P -There is no limit to the number of non-capturing subpatterns, but the maximum -depth of nesting of all kinds of parenthesized subpattern, including capturing -subpatterns, assertions, and other types of subpattern, is 200. +There is no limit to the number of parenthesized subpatterns, but there can be +no more than 65535 capturing subpatterns. .P -The maximum length of name for a named subpattern is 32, and the maximum number -of named subpatterns is 10000. +The maximum length of name for a named subpattern is 32 characters, and the +maximum number of named subpatterns is 10000. .P The maximum length of a subject string is the largest positive number that an integer variable can hold. However, when using the traditional matching @@ -160,7 +163,7 @@ instead of just strings of bytes. .P If you compile PCRE with UTF-8 support, but do not use it at run time, the library will be a bit bigger, but the additional run time overhead is limited -to testing the PCRE_UTF8 flag in several places, so should not be very large. +to testing the PCRE_UTF8 flag occasionally, so should not be very big. .P If PCRE is built with Unicode character property support (which implies UTF-8 support), the escape sequences \ep{..}, \eP{..}, and \eX are supported. @@ -232,13 +235,13 @@ Philip Hazel .br University Computing Service, .br -Cambridge CB2 3QG, England. +Cambridge CB2 3QH, England. .P Putting an actual email address here seems to have been a spam magnet, so I've taken it away. If you want to email me, use my initial and surname, separated by a dot, at the domain ucs.cam.ac.uk. .sp .in 0 -Last updated: 05 June 2006 +Last updated: 23 November 2006 .br Copyright (c) 1997-2006 University of Cambridge. |