95 lines
4.4 KiB
Plaintext
95 lines
4.4 KiB
Plaintext
[/
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Copyright 2006-2007 John Maddock.
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt).
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]
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[section:standards Standards Conformance]
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[h4 C++]
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Boost.Regex is intended to conform to the [tr1].
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[h4 ECMAScript / JavaScript]
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All of the ECMAScript regular expression syntax features are supported, except that:
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The escape sequence \\u matches any upper case character (the same as \[\[:upper:\]\])
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rather than a Unicode escape sequence; use \\x{DDDD} for Unicode escape sequences.
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[h4 Perl]
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Almost all Perl features are supported, except for:
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(?{code}) Not implementable in a compiled strongly typed language.
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(??{code}) Not implementable in a compiled strongly typed language.
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(*VERB) The [@http://perldoc.perl.org/perlre.html#Special-Backtracking-Control-Verbs
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backtracking control verbs] are not recognised or implemented at this time.
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In addition the following features behave slightly differently from Perl:
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^ $ \Z These recognise any line termination sequence, and not just \\n: see the Unicode requirements below.
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[h4 POSIX]
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All the POSIX basic and extended regular expression features are supported,
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except that:
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No character collating names are recognized except those specified in the
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POSIX standard for the C locale, unless they are explicitly registered with the
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traits class.
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Character equivalence classes ( \[\[\=a\=\]\] etc) are probably buggy except on Win32.
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Implementing this feature requires knowledge of the format of the string sort
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keys produced by the system; if you need this, and the default implementation
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doesn't work on your platform, then you will need to supply a custom traits class.
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[h4 Unicode]
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The following comments refer to
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[@http://unicode.org/reports/tr18/ Unicode Technical Standard #18: Unicode
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Regular Expressions version 11].
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[table
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[[Item][Feature][Support]]
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[[1.1][Hex Notation][Yes: use \x{DDDD} to refer to code point UDDDD.]]
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[[1.2][Character Properties][All the names listed under the General Category Property are supported. Script names and Other Names are not currently supported.]]
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[[1.3][Subtraction and Intersection][Indirectly support by forward-lookahead:
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`(?=[[:X:]])[[:Y:]]`
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Gives the intersection of character properties X and Y.
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`(?![[:X:]])[[:Y:]]`
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Gives everything in Y that is not in X (subtraction).]]
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[[1.4][Simple Word Boundaries][Conforming: non-spacing marks are included in the set of word characters.]]
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[[1.5][Caseless Matching][Supported, note that at this level, case transformations are 1:1, many to many case folding operations are not supported (for example "'''ß'''" to "SS").]]
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[[1.6][Line Boundaries][Supported, except that "." matches only one character of "\\r\\n". Other than that word boundaries match correctly; including not matching in the middle of a "\\r\\n" sequence.]]
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[[1.7][Code Points][Supported: provided you use the u32* algorithms, then UTF-8, UTF-16 and UTF-32 are all treated as sequences of 32-bit code points.]]
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[[2.1][Canonical Equivalence][Not supported: it is up to the user of the library to convert all text into the same canonical form as the regular expression.]]
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[[2.2][Default Grapheme Clusters][Not supported.]]
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[[2.3Default Word Boundaries][Not supported.]]
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[[2.4][Default Loose Matches][Not Supported.]]
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[[2.5][Named Properties][Supported: the expression "\[\[:name:\]\]" or \\N{name} matches the named character "name".]]
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[[2.6][Wildcard properties][Not Supported.]]
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[[3.1][Tailored Punctuation.][Not Supported.]]
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[[3.2][Tailored Grapheme Clusters][Not Supported.]]
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[[3.3][Tailored Word Boundaries.][Not Supported.]]
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[[3.4][Tailored Loose Matches][Partial support: \[\[\=c\=\]\] matches characters with the same primary equivalence class as "c".]]
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[[3.5][Tailored Ranges][Supported: \[a-b\] matches any character that collates in the range a to b, when the expression is constructed with the collate flag set.]]
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[[3.6][Context Matches][Not Supported.]]
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[[3.7][Incremental Matches][Supported: pass the flag `match_partial` to the regex algorithms.]]
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[[3.8][Unicode Set Sharing][Not Supported.]]
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[[3.9][Possible Match Sets][Not supported, however this information is used internally to optimise the matching of regular expressions, and return quickly if no match is possible.]]
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[[3.10][Folded Matching][Partial Support: It is possible to achieve a similar effect by using a custom regular expression traits class.]]
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[[3.11][Custom Submatch Evaluation][Not Supported.]]
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]
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[endsect]
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