--- /dev/null
+/////////////////////////////////////////////////////////////////////////////
+// Name: resyn
+// Purpose: topic overview
+// Author: wxWidgets team
+// RCS-ID: $Id$
+// Licence: wxWindows license
+/////////////////////////////////////////////////////////////////////////////
+
+/*!
+
+ @page resyn_overview Syntax of the builtin regular expression library
+
+ A @e regular expression describes strings of characters. It's a
+ pattern that matches certain strings and doesn't match others.
+ @b See also
+ #wxRegEx
+ @ref differentflavors_overview
+ @ref resyntax_overview
+ @ref resynbracket_overview
+ #Escapes
+ #Metasyntax
+ #Matching
+ @ref relimits_overview
+ @ref resynbre_overview
+ @ref resynchars_overview
+
+
+ @section differentflavors Different Flavors of REs
+
+ @ref resyn_overview
+ Regular expressions ("RE''s), as defined by POSIX, come in two
+ flavors: @e extended REs ("EREs'') and @e basic REs ("BREs''). EREs are roughly those
+ of the traditional @e egrep, while BREs are roughly those of the traditional
+ @e ed. This implementation adds a third flavor, @e advanced REs ("AREs''), basically
+ EREs with some significant extensions.
+ This manual page primarily describes
+ AREs. BREs mostly exist for backward compatibility in some old programs;
+ they will be discussed at the #end. POSIX EREs are almost an exact subset
+ of AREs. Features of AREs that are not present in EREs will be indicated.
+
+ @section resyntax Regular Expression Syntax
+
+ @ref resyn_overview
+ These regular expressions are implemented using
+ the package written by Henry Spencer, based on the 1003.2 spec and some
+ (not quite all) of the Perl5 extensions (thanks, Henry!). Much of the description
+ of regular expressions below is copied verbatim from his manual entry.
+ An ARE is one or more @e branches, separated by '@b |', matching anything that matches
+ any of the branches.
+ A branch is zero or more @e constraints or @e quantified
+ atoms, concatenated. It matches a match for the first, followed by a match
+ for the second, etc; an empty branch matches the empty string.
+ A quantified atom is an @e atom possibly followed by a single @e quantifier. Without a quantifier,
+ it matches a match for the atom. The quantifiers, and what a so-quantified
+ atom matches, are:
+
+
+
+
+
+
+ @b *
+
+
+
+
+ a sequence of 0 or more matches of the atom
+
+
+
+
+
+ @b +
+
+
+
+
+ a sequence of 1 or more matches of the atom
+
+
+
+
+
+ @b ?
+
+
+
+
+ a sequence of 0 or 1 matches of the atom
+
+
+
+
+
+ @b {m}
+
+
+
+
+ a sequence of exactly @e m matches of the atom
+
+
+
+
+
+ @b {m,}
+
+
+
+
+ a sequence of @e m or more matches of the atom
+
+
+
+
+
+ @b {m,n}
+
+
+
+
+ a sequence of @e m through @e n (inclusive)
+ matches of the atom; @e m may not exceed @e n
+
+
+
+
+
+ @b *? +? ?? {m}? {m,}? {m,n}?
+
+
+
+
+ @e non-greedy quantifiers,
+ which match the same possibilities, but prefer the
+ smallest number rather than the largest number of matches (see #Matching)
+
+
+
+
+
+ The forms using @b { and @b } are known as @e bounds. The numbers @e m and @e n are unsigned
+ decimal integers with permissible values from 0 to 255 inclusive.
+ An atom is one of:
+
+
+
+
+
+
+ @b (re)
+
+
+
+
+ (where @e re is any regular expression) matches a match for
+ @e re, with the match noted for possible reporting
+
+
+
+
+
+ @b (?:re)
+
+
+
+
+ as previous, but
+ does no reporting (a "non-capturing'' set of parentheses)
+
+
+
+
+
+ @b ()
+
+
+
+
+ matches an empty
+ string, noted for possible reporting
+
+
+
+
+
+ @b (?:)
+
+
+
+
+ matches an empty string, without reporting
+
+
+
+
+
+ @b [chars]
+
+
+
+
+ a @e bracket expression, matching any one of the @e chars
+ (see @ref resynbracket_overview for more detail)
+
+
+
+
+
+ @b .
+
+
+
+
+ matches any single character
+
+
+
+
+
+ @b \k
+
+
+
+
+ (where @e k is a non-alphanumeric character)
+ matches that character taken as an ordinary character, e.g. \\ matches a backslash
+ character
+
+
+
+
+
+ @b \c
+
+
+
+
+ where @e c is alphanumeric (possibly followed by other characters),
+ an @e escape (AREs only), see #Escapes below
+
+
+
+
+
+ @b {
+
+
+
+
+ when followed by a character
+ other than a digit, matches the left-brace character '@b {'; when followed by
+ a digit, it is the beginning of a @e bound (see above)
+
+
+
+
+
+ @b x
+
+
+
+
+ where @e x is a single
+ character with no other significance, matches that character.
+
+
+
+
+
+ A @e constraint matches an empty string when specific conditions are met. A constraint may
+ not be followed by a quantifier. The simple constraints are as follows;
+ some more constraints are described later, under #Escapes.
+
+
+
+
+
+
+ @b ^
+
+
+
+
+ matches at the beginning of a line
+
+
+
+
+
+ @b $
+
+
+
+
+ matches at the end of a line
+
+
+
+
+
+ @b (?=re)
+
+
+
+
+ @e positive lookahead
+ (AREs only), matches at any point where a substring matching @e re begins
+
+
+
+
+
+ @b (?!re)
+
+
+
+
+ @e negative lookahead (AREs only),
+ matches at any point where no substring matching @e re begins
+
+
+
+
+
+ The lookahead constraints may not contain back references
+ (see later), and all parentheses within them are considered non-capturing.
+ An RE may not end with '@b \'.
+
+ @section wxresynbracket Bracket Expressions
+
+ @ref resyn_overview
+ A @e bracket expression is a list
+ of characters enclosed in '@b []'. It normally matches any single character from
+ the list (but see below). If the list begins with '@b ^', it matches any single
+ character (but see below) @e not from the rest of the list.
+ If two characters
+ in the list are separated by '@b -', this is shorthand for the full @e range of
+ characters between those two (inclusive) in the collating sequence, e.g.
+ @b [0-9] in ASCII matches any decimal digit. Two ranges may not share an endpoint,
+ so e.g. @b a-c-e is illegal. Ranges are very collating-sequence-dependent, and portable
+ programs should avoid relying on them.
+ To include a literal @b ] or @b - in the
+ list, the simplest method is to enclose it in @b [. and @b .] to make it a collating
+ element (see below). Alternatively, make it the first character (following
+ a possible '@b ^'), or (AREs only) precede it with '@b \'.
+ Alternatively, for '@b -', make
+ it the last character, or the second endpoint of a range. To use a literal
+ @b - as the first endpoint of a range, make it a collating element or (AREs
+ only) precede it with '@b \'. With the exception of these, some combinations using
+ @b [ (see next paragraphs), and escapes, all other special characters lose
+ their special significance within a bracket expression.
+ Within a bracket
+ expression, a collating element (a character, a multi-character sequence
+ that collates as if it were a single character, or a collating-sequence
+ name for either) enclosed in @b [. and @b .] stands for the
+ sequence of characters of that collating element.
+ @e wxWidgets: Currently no multi-character collating elements are defined.
+ So in @b [.X.], @e X can either be a single character literal or
+ the name of a character. For example, the following are both identical
+ @b [[.0.]-[.9.]] and @b [[.zero.]-[.nine.]] and mean the same as
+ @b [0-9].
+ See @ref resynchars_overview.
+ Within a bracket expression, a collating element enclosed in @b [= and @b =]
+ is an equivalence class, standing for the sequences of characters of all
+ collating elements equivalent to that one, including itself.
+ An equivalence class may not be an endpoint of a range.
+ @e wxWidgets: Currently no equivalence classes are defined, so
+ @b [=X=] stands for just the single character @e X.
+ @e X can either be a single character literal or the name of a character,
+ see @ref resynchars_overview.
+ Within a bracket expression,
+ the name of a @e character class enclosed in @b [: and @b :] stands for the list
+ of all characters (not all collating elements!) belonging to that class.
+ Standard character classes are:
+
+
+
+
+
+
+ @b alpha
+
+
+
+
+ A letter.
+
+
+
+
+
+ @b upper
+
+
+
+
+ An upper-case letter.
+
+
+
+
+
+ @b lower
+
+
+
+
+ A lower-case letter.
+
+
+
+
+
+ @b digit
+
+
+
+
+ A decimal digit.
+
+
+
+
+
+ @b xdigit
+
+
+
+
+ A hexadecimal digit.
+
+
+
+
+
+ @b alnum
+
+
+
+
+ An alphanumeric (letter or digit).
+
+
+
+
+
+ @b print
+
+
+
+
+ An alphanumeric (same as alnum).
+
+
+
+
+
+ @b blank
+
+
+
+
+ A space or tab character.
+
+
+
+
+
+ @b space
+
+
+
+
+ A character producing white space in displayed text.
+
+
+
+
+
+ @b punct
+
+
+
+
+ A punctuation character.
+
+
+
+
+
+ @b graph
+
+
+
+
+ A character with a visible representation.
+
+
+
+
+
+ @b cntrl
+
+
+
+
+ A control character.
+
+
+
+
+
+ A character class may not be used as an endpoint of a range.
+ @e wxWidgets: In a non-Unicode build, these character classifications depend on the
+ current locale, and correspond to the values return by the ANSI C 'is'
+ functions: isalpha, isupper, etc. In Unicode mode they are based on
+ Unicode classifications, and are not affected by the current locale.
+ There are two special cases of bracket expressions:
+ the bracket expressions @b [[::]] and @b [[::]] are constraints, matching empty
+ strings at the beginning and end of a word respectively. A word is defined
+ as a sequence of word characters that is neither preceded nor followed
+ by word characters. A word character is an @e alnum character or an underscore
+ (@b _). These special bracket expressions are deprecated; users of AREs should
+ use constraint escapes instead (see #Escapes below).
+
+ @section wxresynescapes Escapes
+
+ @ref resyn_overview
+ Escapes (AREs only),
+ which begin with a @b \ followed by an alphanumeric character, come in several
+ varieties: character entry, class shorthands, constraint escapes, and back
+ references. A @b \ followed by an alphanumeric character but not constituting
+ a valid escape is illegal in AREs. In EREs, there are no escapes: outside
+ a bracket expression, a @b \ followed by an alphanumeric character merely stands
+ for that character as an ordinary character, and inside a bracket expression,
+ @b \ is an ordinary character. (The latter is the one actual incompatibility
+ between EREs and AREs.)
+ Character-entry escapes (AREs only) exist to make
+ it easier to specify non-printing and otherwise inconvenient characters
+ in REs:
+
+
+
+
+
+
+ @b \a
+
+
+
+
+ alert (bell) character, as in C
+
+
+
+
+
+ @b \b
+
+
+
+
+ backspace, as in C
+
+
+
+
+
+ @b \B
+
+
+
+
+ synonym
+ for @b \ to help reduce backslash doubling in some applications where there
+ are multiple levels of backslash processing
+
+
+
+
+
+ @b \c@e X
+
+
+
+
+ (where X is any character)
+ the character whose low-order 5 bits are the same as those of @e X, and whose
+ other bits are all zero
+
+
+
+
+
+ @b \e
+
+
+
+
+ the character whose collating-sequence name is
+ '@b ESC', or failing that, the character with octal value 033
+
+
+
+
+
+ @b \f
+
+
+
+
+ formfeed, as in C
+
+
+
+
+
+ @b \n
+
+
+
+
+ newline, as in C
+
+
+
+
+
+ @b \r
+
+
+
+
+ carriage return, as in C
+
+
+
+
+
+ @b \t
+
+
+
+
+ horizontal tab, as in C
+
+
+
+
+
+ @b \u@e wxyz
+
+
+
+
+ (where @e wxyz is exactly four hexadecimal digits)
+ the Unicode
+ character @b U+@e wxyz in the local byte ordering
+
+
+
+
+
+ @b \U@e stuvwxyz
+
+
+
+
+ (where @e stuvwxyz is
+ exactly eight hexadecimal digits) reserved for a somewhat-hypothetical Unicode
+ extension to 32 bits
+
+
+
+
+
+ @b \v
+
+
+
+
+ vertical tab, as in C are all available.
+
+
+
+
+
+ @b \x@e hhh
+
+
+
+
+ (where
+ @e hhh is any sequence of hexadecimal digits) the character whose hexadecimal
+ value is @b 0x@e hhh (a single character no matter how many hexadecimal digits
+ are used).
+
+
+
+
+
+ @b \0
+
+
+
+
+ the character whose value is @b 0
+
+
+
+
+
+ @b \@e xy
+
+
+
+
+ (where @e xy is exactly two
+ octal digits, and is not a @e back reference (see below)) the character whose
+ octal value is @b 0@e xy
+
+
+
+
+
+ @b \@e xyz
+
+
+
+
+ (where @e xyz is exactly three octal digits, and is
+ not a back reference (see below))
+ the character whose octal value is @b 0@e xyz
+
+
+
+
+
+ Hexadecimal digits are '@b 0'-'@b 9', '@b a'-'@b f', and '@b A'-'@b F'. Octal
+ digits are '@b 0'-'@b 7'.
+ The character-entry
+ escapes are always taken as ordinary characters. For example, @b \135 is @b ] in
+ ASCII, but @b \135 does not terminate a bracket expression. Beware, however,
+ that some applications (e.g., C compilers) interpret such sequences themselves
+ before the regular-expression package gets to see them, which may require
+ doubling (quadrupling, etc.) the '@b \'.
+ Class-shorthand escapes (AREs only) provide
+ shorthands for certain commonly-used character classes:
+
+
+
+
+
+
+ @b \d
+
+
+
+
+ @b [[:digit:]]
+
+
+
+
+
+ @b \s
+
+
+
+
+ @b [[:space:]]
+
+
+
+
+
+ @b \w
+
+
+
+
+ @b [[:alnum:]_] (note underscore)
+
+
+
+
+
+ @b \D
+
+
+
+
+ @b [^[:digit:]]
+
+
+
+
+
+ @b \S
+
+
+
+
+ @b [^[:space:]]
+
+
+
+
+
+ @b \W
+
+
+
+
+ @b [^[:alnum:]_] (note underscore)
+
+
+
+
+
+ Within bracket expressions, '@b \d', '@b \s', and
+ '@b \w' lose their outer brackets, and '@b \D',
+ '@b \S', and '@b \W' are illegal. (So, for example,
+ @b [a-c\d] is equivalent to @b [a-c[:digit:]].
+ Also, @b [a-c\D], which is equivalent to
+ @b [a-c^[:digit:]], is illegal.)
+ A constraint escape (AREs only) is a constraint,
+ matching the empty string if specific conditions are met, written as an
+ escape:
+
+
+
+
+
+
+ @b \A
+
+
+
+
+ matches only at the beginning of the string
+ (see #Matching, below,
+ for how this differs from '@b ^')
+
+
+
+
+
+ @b \m
+
+
+
+
+ matches only at the beginning of a word
+
+
+
+
+
+ @b \M
+
+
+
+
+ matches only at the end of a word
+
+
+
+
+
+ @b \y
+
+
+
+
+ matches only at the beginning or end of a word
+
+
+
+
+
+ @b \Y
+
+
+
+
+ matches only at a point that is not the beginning or end of
+ a word
+
+
+
+
+
+ @b \Z
+
+
+
+
+ matches only at the end of the string
+ (see #Matching, below, for
+ how this differs from '@b $')
+
+
+
+
+
+ @b \@e m
+
+
+
+
+ (where @e m is a nonzero digit) a @e back reference,
+ see below
+
+
+
+
+
+ @b \@e mnn
+
+
+
+
+ (where @e m is a nonzero digit, and @e nn is some more digits,
+ and the decimal value @e mnn is not greater than the number of closing capturing
+ parentheses seen so far) a @e back reference, see below
+
+
+
+
+
+ A word is defined
+ as in the specification of @b [[::]] and @b [[::]] above. Constraint escapes are
+ illegal within bracket expressions.
+ A back reference (AREs only) matches
+ the same string matched by the parenthesized subexpression specified by
+ the number, so that (e.g.) @b ([bc])\1 matches @b bb or @b cc but not '@b bc'.
+ The subexpression
+ must entirely precede the back reference in the RE. Subexpressions are numbered
+ in the order of their leading parentheses. Non-capturing parentheses do not
+ define subexpressions.
+ There is an inherent historical ambiguity between
+ octal character-entry escapes and back references, which is resolved by
+ heuristics, as hinted at above. A leading zero always indicates an octal
+ escape. A single non-zero digit, not followed by another digit, is always
+ taken as a back reference. A multi-digit sequence not starting with a zero
+ is taken as a back reference if it comes after a suitable subexpression
+ (i.e. the number is in the legal range for a back reference), and otherwise
+ is taken as octal.
+
+ @section remetasyntax Metasyntax
+
+ @ref resyn_overview
+ In addition to the main syntax described above,
+ there are some special forms and miscellaneous syntactic facilities available.
+ Normally the flavor of RE being used is specified by application-dependent
+ means. However, this can be overridden by a @e director. If an RE of any flavor
+ begins with '@b ***:', the rest of the RE is an ARE. If an RE of any flavor begins
+ with '@b ***=', the rest of the RE is taken to be a literal string, with all
+ characters considered ordinary characters.
+ An ARE may begin with @e embedded options: a sequence @b (?xyz)
+ (where @e xyz is one or more alphabetic characters)
+ specifies options affecting the rest of the RE. These supplement, and can
+ override, any options specified by the application. The available option
+ letters are:
+
+
+
+
+
+
+ @b b
+
+
+
+
+ rest of RE is a BRE
+
+
+
+
+
+ @b c
+
+
+
+
+ case-sensitive matching (usual default)
+
+
+
+
+
+ @b e
+
+
+
+
+ rest of RE is an ERE
+
+
+
+
+
+ @b i
+
+
+
+
+ case-insensitive matching (see #Matching, below)
+
+
+
+
+
+ @b m
+
+
+
+
+ historical synonym for @b n
+
+
+
+
+
+ @b n
+
+
+
+
+ newline-sensitive matching (see #Matching, below)
+
+
+
+
+
+ @b p
+
+
+
+
+ partial newline-sensitive matching (see #Matching, below)
+
+
+
+
+
+ @b q
+
+
+
+
+ rest of RE
+ is a literal ("quoted'') string, all ordinary characters
+
+
+
+
+
+ @b s
+
+
+
+
+ non-newline-sensitive matching (usual default)
+
+
+
+
+
+ @b t
+
+
+
+
+ tight syntax (usual default; see below)
+
+
+
+
+
+ @b w
+
+
+
+
+ inverse
+ partial newline-sensitive ("weird'') matching (see #Matching, below)
+
+
+
+
+
+ @b x
+
+
+
+
+ expanded syntax (see below)
+
+
+
+
+
+ Embedded options take effect at the @b ) terminating the
+ sequence. They are available only at the start of an ARE, and may not be
+ used later within it.
+ In addition to the usual (@e tight) RE syntax, in which
+ all characters are significant, there is an @e expanded syntax, available
+ in AREs with the embedded
+ x option. In the expanded syntax, white-space characters are ignored and
+ all characters between a @b # and the following newline (or the end of the
+ RE) are ignored, permitting paragraphing and commenting a complex RE. There
+ are three exceptions to that basic rule:
+
+
+ a white-space character or '@b #' preceded
+ by '@b \' is retained
+ white space or '@b #' within a bracket expression is retained
+ white space and comments are illegal within multi-character symbols like
+ the ARE '@b (?:' or the BRE '@b \('
+
+
+ Expanded-syntax white-space characters are blank,
+ tab, newline, and any character that belongs to the @e space character class.
+ Finally, in an ARE, outside bracket expressions, the sequence '@b (?#ttt)' (where
+ @e ttt is any text not containing a '@b )') is a comment, completely ignored. Again,
+ this is not allowed between the characters of multi-character symbols like
+ '@b (?:'. Such comments are more a historical artifact than a useful facility,
+ and their use is deprecated; use the expanded syntax instead.
+ @e None of these
+ metasyntax extensions is available if the application (or an initial @b ***=
+ director) has specified that the user's input be treated as a literal string
+ rather than as an RE.
+
+ @section wxresynmatching Matching
+
+ @ref resyn_overview
+ In the event that an RE could match more than
+ one substring of a given string, the RE matches the one starting earliest
+ in the string. If the RE could match more than one substring starting at
+ that point, its choice is determined by its @e preference: either the longest
+ substring, or the shortest.
+ Most atoms, and all constraints, have no preference.
+ A parenthesized RE has the same preference (possibly none) as the RE. A
+ quantified atom with quantifier @b {m} or @b {m}? has the same preference (possibly
+ none) as the atom itself. A quantified atom with other normal quantifiers
+ (including @b {m,n} with @e m equal to @e n) prefers longest match. A quantified
+ atom with other non-greedy quantifiers (including @b {m,n}? with @e m equal to
+ @e n) prefers shortest match. A branch has the same preference as the first
+ quantified atom in it which has a preference. An RE consisting of two or
+ more branches connected by the @b | operator prefers longest match.
+ Subject to the constraints imposed by the rules for matching the whole RE, subexpressions
+ also match the longest or shortest possible substrings, based on their
+ preferences, with subexpressions starting earlier in the RE taking priority
+ over ones starting later. Note that outer subexpressions thus take priority
+ over their component subexpressions.
+ Note that the quantifiers @b {1,1} and
+ @b {1,1}? can be used to force longest and shortest preference, respectively,
+ on a subexpression or a whole RE.
+ Match lengths are measured in characters,
+ not collating elements. An empty string is considered longer than no match
+ at all. For example, @b bb* matches the three middle characters
+ of '@b abbbc', @b (week|wee)(night|knights)
+ matches all ten characters of '@b weeknights', when @b (.*).* is matched against
+ @b abc the parenthesized subexpression matches all three characters, and when
+ @b (a*)* is matched against @b bc both the whole RE and the parenthesized subexpression
+ match an empty string.
+ If case-independent matching is specified, the effect
+ is much as if all case distinctions had vanished from the alphabet. When
+ an alphabetic that exists in multiple cases appears as an ordinary character
+ outside a bracket expression, it is effectively transformed into a bracket
+ expression containing both cases, so that @b x becomes '@b [xX]'. When it appears
+ inside a bracket expression, all case counterparts of it are added to the
+ bracket expression, so that @b [x] becomes @b [xX] and @b [^x] becomes '@b [^xX]'.
+ If newline-sensitive
+ matching is specified, @b . and bracket expressions using @b ^ will never match
+ the newline character (so that matches will never cross newlines unless
+ the RE explicitly arranges it) and @b ^ and @b $ will match the empty string after
+ and before a newline respectively, in addition to matching at beginning
+ and end of string respectively. ARE @b \A and @b \Z continue to match beginning
+ or end of string @e only.
+ If partial newline-sensitive matching is specified,
+ this affects @b . and bracket expressions as with newline-sensitive matching,
+ but not @b ^ and '@b $'.
+ If inverse partial newline-sensitive matching is specified,
+ this affects @b ^ and @b $ as with newline-sensitive matching, but not @b . and bracket
+ expressions. This isn't very useful but is provided for symmetry.
+
+ @section relimits Limits And Compatibility
+
+ @ref resyn_overview
+ No particular limit is imposed on the length of REs. Programs
+ intended to be highly portable should not employ REs longer than 256 bytes,
+ as a POSIX-compliant implementation can refuse to accept such REs.
+ The only
+ feature of AREs that is actually incompatible with POSIX EREs is that @b \
+ does not lose its special significance inside bracket expressions. All other
+ ARE features use syntax which is illegal or has undefined or unspecified
+ effects in POSIX EREs; the @b *** syntax of directors likewise is outside
+ the POSIX syntax for both BREs and EREs.
+ Many of the ARE extensions are
+ borrowed from Perl, but some have been changed to clean them up, and a
+ few Perl extensions are not present. Incompatibilities of note include '@b \b',
+ '@b \B', the lack of special treatment for a trailing newline, the addition of
+ complemented bracket expressions to the things affected by newline-sensitive
+ matching, the restrictions on parentheses and back references in lookahead
+ constraints, and the longest/shortest-match (rather than first-match) matching
+ semantics.
+ The matching rules for REs containing both normal and non-greedy
+ quantifiers have changed since early beta-test versions of this package.
+ (The new rules are much simpler and cleaner, but don't work as hard at guessing
+ the user's real intentions.)
+ Henry Spencer's original 1986 @e regexp package, still in widespread use,
+ implemented an early version of today's EREs. There are four incompatibilities between @e regexp's
+ near-EREs ('RREs' for short) and AREs. In roughly increasing order of significance:
+
+
+ In AREs, @b \ followed by an alphanumeric character is either an escape or
+ an error, while in RREs, it was just another way of writing the alphanumeric.
+ This should not be a problem because there was no reason to write such
+ a sequence in RREs.
+ @b { followed by a digit in an ARE is the beginning of
+ a bound, while in RREs, @b { was always an ordinary character. Such sequences
+ should be rare, and will often result in an error because following characters
+ will not look like a valid bound.
+ In AREs, @b \ remains a special character
+ within '@b []', so a literal @b \ within @b [] must be
+ written '@b \\'. @b \\ also gives a literal
+ @b \ within @b [] in RREs, but only truly paranoid programmers routinely doubled
+ the backslash.
+ AREs report the longest/shortest match for the RE, rather
+ than the first found in a specified search order. This may affect some RREs
+ which were written in the expectation that the first match would be reported.
+ (The careful crafting of RREs to optimize the search order for fast matching
+ is obsolete (AREs examine all possible matches in parallel, and their performance
+ is largely insensitive to their complexity) but cases where the search
+ order was exploited to deliberately find a match which was @e not the longest/shortest
+ will need rewriting.)
+
+
+
+ @section wxresynbre Basic Regular Expressions
+
+ @ref resyn_overview
+ BREs differ from EREs in
+ several respects. '@b |', '@b +', and @b ? are ordinary characters and there is no equivalent
+ for their functionality. The delimiters for bounds
+ are @b \{ and '@b \}', with @b { and
+ @b } by themselves ordinary characters. The parentheses for nested subexpressions
+ are @b \( and '@b \)', with @b ( and @b ) by themselves
+ ordinary characters. @b ^ is an ordinary
+ character except at the beginning of the RE or the beginning of a parenthesized
+ subexpression, @b $ is an ordinary character except at the end of the RE or
+ the end of a parenthesized subexpression, and @b * is an ordinary character
+ if it appears at the beginning of the RE or the beginning of a parenthesized
+ subexpression (after a possible leading '@b ^'). Finally, single-digit back references
+ are available, and @b \ and @b \ are synonyms
+ for @b [[::]] and @b [[::]] respectively;
+ no other escapes are available.
+
+ @section wxresynchars Regular Expression Character Names
+
+ @ref resyn_overview
+ Note that the character names are case sensitive.
+
+
+
+
+
+
+ NUL
+
+
+
+
+ '\0'
+
+
+
+
+
+ SOH
+
+
+
+
+ '\001'
+
+
+
+
+
+ STX
+
+
+
+
+ '\002'
+
+
+
+
+
+ ETX
+
+
+
+
+ '\003'
+
+
+
+
+
+ EOT
+
+
+
+
+ '\004'
+
+
+
+
+
+ ENQ
+
+
+
+
+ '\005'
+
+
+
+
+
+ ACK
+
+
+
+
+ '\006'
+
+
+
+
+
+ BEL
+
+
+
+
+ '\007'
+
+
+
+
+
+ alert
+
+
+
+
+ '\007'
+
+
+
+
+
+ BS
+
+
+
+
+ '\010'
+
+
+
+
+
+ backspace
+
+
+
+
+ '\b'
+
+
+
+
+
+ HT
+
+
+
+
+ '\011'
+
+
+
+
+
+ tab
+
+
+
+
+ '\t'
+
+
+
+
+
+ LF
+
+
+
+
+ '\012'
+
+
+
+
+
+ newline
+
+
+
+
+ '\n'
+
+
+
+
+
+ VT
+
+
+
+
+ '\013'
+
+
+
+
+
+ vertical-tab
+
+
+
+
+ '\v'
+
+
+
+
+
+ FF
+
+
+
+
+ '\014'
+
+
+
+
+
+ form-feed
+
+
+
+
+ '\f'
+
+
+
+
+
+ CR
+
+
+
+
+ '\015'
+
+
+
+
+
+ carriage-return
+
+
+
+
+ '\r'
+
+
+
+
+
+ SO
+
+
+
+
+ '\016'
+
+
+
+
+
+ SI
+
+
+
+
+ '\017'
+
+
+
+
+
+ DLE
+
+
+
+
+ '\020'
+
+
+
+
+
+ DC1
+
+
+
+
+ '\021'
+
+
+
+
+
+ DC2
+
+
+
+
+ '\022'
+
+
+
+
+
+ DC3
+
+
+
+
+ '\023'
+
+
+
+
+
+ DC4
+
+
+
+
+ '\024'
+
+
+
+
+
+ NAK
+
+
+
+
+ '\025'
+
+
+
+
+
+ SYN
+
+
+
+
+ '\026'
+
+
+
+
+
+ ETB
+
+
+
+
+ '\027'
+
+
+
+
+
+ CAN
+
+
+
+
+ '\030'
+
+
+
+
+
+ EM
+
+
+
+
+ '\031'
+
+
+
+
+
+ SUB
+
+
+
+
+ '\032'
+
+
+
+
+
+ ESC
+
+
+
+
+ '\033'
+
+
+
+
+
+ IS4
+
+
+
+
+ '\034'
+
+
+
+
+
+ FS
+
+
+
+
+ '\034'
+
+
+
+
+
+ IS3
+
+
+
+
+ '\035'
+
+
+
+
+
+ GS
+
+
+
+
+ '\035'
+
+
+
+
+
+ IS2
+
+
+
+
+ '\036'
+
+
+
+
+
+ RS
+
+
+
+
+ '\036'
+
+
+
+
+
+ IS1
+
+
+
+
+ '\037'
+
+
+
+
+
+ US
+
+
+
+
+ '\037'
+
+
+
+
+
+ space
+
+
+
+
+ ' '
+
+
+
+
+
+ exclamation-mark
+
+
+
+
+ '!'
+
+
+
+
+
+ quotation-mark
+
+
+
+
+ '"'
+
+
+
+
+
+ number-sign
+
+
+
+
+ '#'
+
+
+
+
+
+ dollar-sign
+
+
+
+
+ '$'
+
+
+
+
+
+ percent-sign
+
+
+
+
+ '%'
+
+
+
+
+
+ ampersand
+
+
+
+
+ ''
+
+
+
+
+
+ apostrophe
+
+
+
+
+ '\''
+
+
+
+
+
+ left-parenthesis
+
+
+
+
+ '('
+
+
+
+
+
+ right-parenthesis
+
+
+
+
+ ')'
+
+
+
+
+
+ asterisk
+
+
+
+
+ '*'
+
+
+
+
+
+ plus-sign
+
+
+
+
+ '+'
+
+
+
+
+
+ comma
+
+
+
+
+ ','
+
+
+
+
+
+ hyphen
+
+
+
+
+ '-'
+
+
+
+
+
+ hyphen-minus
+
+
+
+
+ '-'
+
+
+
+
+
+ period
+
+
+
+
+ '.'
+
+
+
+
+
+ full-stop
+
+
+
+
+ '.'
+
+
+
+
+
+ slash
+
+
+
+
+ '/'
+
+
+
+
+
+ solidus
+
+
+
+
+ '/'
+
+
+
+
+
+ zero
+
+
+
+
+ '0'
+
+
+
+
+
+ one
+
+
+
+
+ '1'
+
+
+
+
+
+ two
+
+
+
+
+ '2'
+
+
+
+
+
+ three
+
+
+
+
+ '3'
+
+
+
+
+
+ four
+
+
+
+
+ '4'
+
+
+
+
+
+ five
+
+
+
+
+ '5'
+
+
+
+
+
+ six
+
+
+
+
+ '6'
+
+
+
+
+
+ seven
+
+
+
+
+ '7'
+
+
+
+
+
+ eight
+
+
+
+
+ '8'
+
+
+
+
+
+ nine
+
+
+
+
+ '9'
+
+
+
+
+
+ colon
+
+
+
+
+ ':'
+
+
+
+
+
+ semicolon
+
+
+
+
+ ';'
+
+
+
+
+
+ less-than-sign
+
+
+
+
+ ''
+
+
+
+
+
+ equals-sign
+
+
+
+
+ '='
+
+
+
+
+
+ greater-than-sign
+
+
+
+
+ ''
+
+
+
+
+
+ question-mark
+
+
+
+
+ '?'
+
+
+
+
+
+ commercial-at
+
+
+
+
+ '@'
+
+
+
+
+
+ left-square-bracket
+
+
+
+
+ '['
+
+
+
+
+
+ backslash
+
+
+
+
+ '\'
+
+
+
+
+
+ reverse-solidus
+
+
+
+
+ '\'
+
+
+
+
+
+ right-square-bracket
+
+
+
+
+ ']'
+
+
+
+
+
+ circumflex
+
+
+
+
+ '^'
+
+
+
+
+
+ circumflex-accent
+
+
+
+
+ '^'
+
+
+
+
+
+ underscore
+
+
+
+
+ '_'
+
+
+
+
+
+ low-line
+
+
+
+
+ '_'
+
+
+
+
+
+ grave-accent
+
+
+
+
+ '''
+
+
+
+
+
+ left-brace
+
+
+
+
+ '{'
+
+
+
+
+
+ left-curly-bracket
+
+
+
+
+ '{'
+
+
+
+
+
+ vertical-line
+
+
+
+
+ '|'
+
+
+
+
+
+ right-brace
+
+
+
+
+ '}'
+
+
+
+
+
+ right-curly-bracket
+
+
+
+
+ '}'
+
+
+
+
+
+ tilde
+
+
+
+
+ '~'
+
+
+
+
+
+ DEL
+
+
+
+
+ '\177'
+
+ */
+
+
projects / wxWidgets.git / blobdiff