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revision 442 by ph10, Fri Sep 11 10:21:02 2009 UTC revision 453 by ph10, Fri Sep 18 19:12:35 2009 UTC
# Line 46  encountered by PCRE, an error is generat Line 46  encountered by PCRE, an error is generat
46  built with Unicode character property support. The properties that can be  built with Unicode character property support. The properties that can be
47  tested with \ep and \eP are limited to the general category properties such as  tested with \ep and \eP are limited to the general category properties such as
48  Lu and Nd, script names such as Greek or Han, and the derived properties Any  Lu and Nd, script names such as Greek or Han, and the derived properties Any
49  and L&.  and L&. PCRE does support the Cs (surrogate) property, which Perl does not; the
50    Perl documentation says "Because Perl hides the need for the user to understand
51    the internal representation of Unicode characters, there is no need to
52    implement the somewhat messy concept of surrogates."
53  .P  .P
54  7. PCRE does support the \eQ...\eE escape for quoting substrings. Characters in  7. PCRE does support the \eQ...\eE escape for quoting substrings. Characters in
55  between are treated as literals. This is slightly different from Perl in that $  between are treated as literals. This is slightly different from Perl in that $
# Line 66  The \eQ...\eE sequence is recognized bot Line 69  The \eQ...\eE sequence is recognized bot
69  .P  .P
70  8. Fairly obviously, PCRE does not support the (?{code}) and (??{code})  8. Fairly obviously, PCRE does not support the (?{code}) and (??{code})
71  constructions. However, there is support for recursive patterns. This is not  constructions. However, there is support for recursive patterns. This is not
72  available in Perl 5.8, but will be in Perl 5.10. Also, the PCRE "callout"  available in Perl 5.8, but it is in Perl 5.10. Also, the PCRE "callout"
73  feature allows an external function to be called during pattern matching. See  feature allows an external function to be called during pattern matching. See
74  the  the
75  .\" HREF  .\" HREF
# Line 75  the Line 78  the
78  documentation for details.  documentation for details.
79  .P  .P
80  9. Subpatterns that are called recursively or as "subroutines" are always  9. Subpatterns that are called recursively or as "subroutines" are always
81  treated as atomic groups in PCRE. This is like Python, but unlike Perl.  treated as atomic groups in PCRE. This is like Python, but unlike Perl. There
82    is a discussion of an example that explains this in more detail in the
83    .\" HTML <a href="pcrepattern.html#recursiondifference">
84    .\" </a>
85    section on recursion differences from Perl
86    .\"
87    in the
88    .\" HREF
89    \fBpcrecompat\fP
90    .\"
91    page.
92  .P  .P
93  10. There are some differences that are concerned with the settings of captured  10. There are some differences that are concerned with the settings of captured
94  strings when part of a pattern is repeated. For example, matching "aba" against  strings when part of a pattern is repeated. For example, matching "aba" against
# Line 83  the pattern /^(a(b)?)+$/ in Perl leaves Line 96  the pattern /^(a(b)?)+$/ in Perl leaves
96  .P  .P
97  11. PCRE does support Perl 5.10's backtracking verbs (*ACCEPT), (*FAIL), (*F),  11. PCRE does support Perl 5.10's backtracking verbs (*ACCEPT), (*FAIL), (*F),
98  (*COMMIT), (*PRUNE), (*SKIP), and (*THEN), but only in the forms without an  (*COMMIT), (*PRUNE), (*SKIP), and (*THEN), but only in the forms without an
99  argument. PCRE does not support (*MARK). If (*ACCEPT) is within capturing  argument. PCRE does not support (*MARK).
 parentheses, PCRE does not set that capture group; this is different to Perl.  
100  .P  .P
101  12. PCRE provides some extensions to the Perl regular expression facilities.  12. PCRE provides some extensions to the Perl regular expression facilities.
102  Perl 5.10 will include new features that are not in earlier versions, some of  Perl 5.10 will include new features that are not in earlier versions, some of
# Line 143  Cambridge CB2 3QH, England. Line 155  Cambridge CB2 3QH, England.
155  .rs  .rs
156  .sp  .sp
157  .nf  .nf
158  Last updated: 11 September 2009  Last updated: 18 September 2009
159  Copyright (c) 1997-2009 University of Cambridge.  Copyright (c) 1997-2009 University of Cambridge.
160  .fi  .fi
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