\helpref{wxRegEx}{wxregex}
-
-\subsection{Different Flavors of REs}
+\subsection{Different Flavors of REs}\label{differentflavors}
\helpref{Syntax of the builtin regular expression library}{wxresyn}
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 \helpref{end}{wxresynbre}. POSIX EREs are almost an exact subset
-of AREs. Features of AREs that are not present in EREs will be indicated.
+AREs. BREs mostly exist for backward compatibility in some old programs;
+they will be discussed at the \helpref{end}{wxresynbre}. POSIX EREs are almost an exact subset
+of AREs. Features of AREs that are not present in EREs will be indicated.
-
-\subsection{Regular Expression Syntax}
+\subsection{Regular Expression Syntax}\label{resyntax}
\helpref{Syntax of the builtin regular expression library}{wxresyn}
(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 {\it branches}, separated by `{\bf $|$}', matching anything that matches
+An ARE is one or more {\it branches}, separated by `{\bf $|$}', matching anything that matches
any of the branches.
A branch is zero or more {\it constraints} or {\it 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 {\it atom} possibly followed by a single {\it quantifier}. Without a quantifier,
+A quantified atom is an {\it atom} possibly followed by a single {\it quantifier}. Without a quantifier,
it matches a match for the atom. The quantifiers, and what a so-quantified
atom matches, are:
character with no other significance, matches that character.}
\end{twocollist}
-A {\it constraint}
-matches an empty string when specific conditions are met. A constraint may
+A {\it 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 \helpref{Escapes}{wxresynescapes}.
\begin{twocollist}\twocolwidtha{4cm}
-\twocolitem{{\bf $^$}}{matches at the beginning of a line}
+\twocolitem{{\bf \caret}}{matches at the beginning of a line}
\twocolitem{{\bf \$}}{matches at the end of a line}
\twocolitem{{\bf (?=re)}}{{\it positive lookahead}
(AREs only), matches at any point where a substring matching {\it re} begins}
An RE may not end with `{\bf $\backslash$}'.
-
\subsection{Bracket Expressions}\label{wxresynbracket}
\helpref{Syntax of the builtin regular expression library}{wxresyn}
A {\it bracket expression} is a list
of characters enclosed in `{\bf $[]$}'. It normally matches any single character from
-the list (but see below). If the list begins with `{\bf $^$}', it matches any single
+the list (but see below). If the list begins with `{\bf \caret}', it matches any single
character (but see below) {\it not} from the rest of the list.
If two characters
To include a literal {\bf $]$} or {\bf -} in the
list, the simplest method is to enclose it in {\bf $[.$} and {\bf $.]$} to make it a collating
element (see below). Alternatively, make it the first character (following
-a possible `{\bf $^$}'), or (AREs only) precede it with `{\bf $\backslash$}'.
+a possible `{\bf \caret}'), or (AREs only) precede it with `{\bf $\backslash$}'.
Alternatively, for `{\bf -}', make
it the last character, or the second endpoint of a range. To use a literal
{\bf -} as the first endpoint of a range, make it a collating element or (AREs
name for either) enclosed in {\bf $[.$} and {\bf $.]$} stands for the
sequence of characters of that collating element.
-{\it wxWindows}: Currently no multi-character collating elements are defined.
+{\it wxWidgets}: Currently no multi-character collating elements are defined.
So in {\bf $[.X.]$}, {\it X} can either be a single character literal or
the name of a character. For example, the following are both identical
{\bf $[[.0.]-[.9.]]$} and {\bf $[[.zero.]-[.nine.]]$} and mean the same as
%The sequence is a single element of the bracket
%expression's list. A bracket expression in a locale that has multi-character
%collating elements can thus match more than one character. So (insidiously),
-%a bracket expression that starts with {\bf $^$} can match multi-character collating
+%a bracket expression that starts with {\bf \caret} can match multi-character collating
%elements even if none of them appear in the bracket expression! ({\it Note:}
%Tcl currently has no multi-character collating elements. This information
%is only for illustration.)
%(If there are
%no other equivalent collating elements, the treatment is as if the enclosing
%delimiters were `{\bf $[.$}' and `{\bf $.]$}'.) For example, if {\bf o}
-%and {\bf $^$} are the members of an
-%equivalence class, then `{\bf $[[$=o=$]]$}', `{\bf $[[$=$^$=$]]$}',
+%and {\bf \caret} are the members of an
+%equivalence class, then `{\bf $[[$=o=$]]$}', `{\bf $[[$=\caret=$]]$}',
%and `{\bf $[o^]$}' are all synonymous.
An equivalence class may not be an endpoint of a range.
%implements only the Unicode locale. It doesn't define any equivalence classes.
%The examples above are just illustrations.)
-{\it wxWindows}: Currently no equivalence classes are defined, so
+{\it wxWidgets}: Currently no equivalence classes are defined, so
{\bf $[=X=]$} stands for just the single character {\it X}.
{\it X} can either be a single character literal or the name of a character,
see \helpref{Character Names}{wxresynchars}.
%implementation has only one locale: the Unicode locale.)
A character class may not be used as an endpoint of a range.
-{\it wxWindows:} In a non-Unicode build, these character classifications depend on the
+{\it 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.
({\bf \_}). These special bracket expressions are deprecated; users of AREs should
use constraint escapes instead (see \helpref{Escapes}{wxresynescapes} below).
-
\subsection{Escapes}\label{wxresynescapes}
\helpref{Syntax of the builtin regular expression library}{wxresyn}
\begin{twocollist}\twocolwidtha{4cm}
\twocolitem{{\bf $\backslash$A}}{matches only at the beginning of the string
(see \helpref{Matching}{wxresynmatching}, below,
-for how this differs from `{\bf $^$}')}
+for how this differs from `{\bf \caret}')}
\twocolitem{{\bf $\backslash$m}}{matches only at the beginning of a word}
\twocolitem{{\bf $\backslash$M}}{matches only at the end of a word}
\twocolitem{{\bf $\backslash$y}}{matches only at the beginning or end of a word}
(i.e. the number is in the legal range for a back reference), and otherwise
is taken as octal.
-
-\subsection{Metasyntax}
+\subsection{Metasyntax}\label{remetasyntax}
\helpref{Syntax of the builtin regular expression library}{wxresyn}
director) has specified that the user's input be treated as a literal string
rather than as an RE.
-
\subsection{Matching}\label{wxresynmatching}
\helpref{Syntax of the builtin regular expression library}{wxresyn}
quantified atom in it which has a preference. An RE consisting of two or
more branches connected by the {\bf $|$} operator prefers longest match.
-Subject
-to the constraints imposed by the rules for matching the whole RE, subexpressions
+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
bracket expression, so that {\bf $[x]$} becomes {\bf $[xX]$} and {\bf $[^x]$} becomes `{\bf $[^xX]$}'.
If newline-sensitive
-matching is specified, {\bf .} and bracket expressions using {\bf $^$} will never match
+matching is specified, {\bf .} and bracket expressions using {\bf \caret} will never match
the newline character (so that matches will never cross newlines unless
-the RE explicitly arranges it) and {\bf $^$} and {\bf \$} will match the empty string after
+the RE explicitly arranges it) and {\bf \caret} and {\bf \$} will match the empty string after
and before a newline respectively, in addition to matching at beginning
and end of string respectively. ARE {\bf $\backslash$A} and {\bf $\backslash$Z} continue to match beginning
or end of string {\it only}.
If partial newline-sensitive matching is specified,
this affects {\bf .} and bracket expressions as with newline-sensitive matching,
-but not {\bf $^$} and `{\bf \$}'.
+but not {\bf \caret} and `{\bf \$}'.
If inverse partial newline-sensitive matching is specified,
-this affects {\bf $^$} and {\bf \$} as with newline-sensitive matching, but not {\bf .} and bracket
+this affects {\bf \caret} and {\bf \$} as with newline-sensitive matching, but not {\bf .} and bracket
expressions. This isn't very useful but is provided for symmetry.
-
-\subsection{Limits And Compatibility}
+\subsection{Limits And Compatibility}\label{relimits}
\helpref{Syntax of the builtin regular expression library}{wxresyn}
implemented an early version of today's EREs. There are four incompatibilities between {\it regexp}'s
near-EREs (`RREs' for short) and AREs. In roughly increasing order of significance:
{\itemize
-\item
-In AREs, {\bf $\backslash$} followed by an alphanumeric character is either an escape or
+\item In AREs, {\bf $\backslash$} 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.
-\item%
-{\bf \{} followed by a digit in an ARE is the beginning of
+\item {\bf \{} followed by a digit in an ARE is the beginning of
a bound, while in RREs, {\bf \{} 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.
-\item%
-In AREs, {\bf $\backslash$} remains a special character
+\item In AREs, {\bf $\backslash$} remains a special character
within `{\bf $[]$}', so a literal {\bf $\backslash$} within {\bf $[]$} must be
written `{\bf $\backslash\backslash$}'. {\bf $\backslash\backslash$} also gives a literal
{\bf $\backslash$} within {\bf $[]$} in RREs, but only truly paranoid programmers routinely doubled
the backslash.
-\item%
-AREs report the longest/shortest match for the RE, rather
+\item 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
will need rewriting.)
}
-
\subsection{Basic Regular Expressions}\label{wxresynbre}
\helpref{Syntax of the builtin regular expression library}{wxresyn}
are {\bf $\backslash$\{} and `{\bf $\backslash$\}}', with {\bf \{} and
{\bf \}} by themselves ordinary characters. The parentheses for nested subexpressions
are {\bf $\backslash$(} and `{\bf $\backslash$)}', with {\bf (} and {\bf )} by themselves
-ordinary characters. {\bf $^$} is an ordinary
+ordinary characters. {\bf \caret} is an ordinary
character except at the beginning of the RE or the beginning of a parenthesized
subexpression, {\bf \$} is an ordinary character except at the end of the RE or
the end of a parenthesized subexpression, and {\bf *} is an ordinary character
if it appears at the beginning of the RE or the beginning of a parenthesized
-subexpression (after a possible leading `{\bf $^$}'). Finally, single-digit back references
+subexpression (after a possible leading `{\bf \caret}'). Finally, single-digit back references
are available, and {\bf $\backslash<$} and {\bf $\backslash>$} are synonyms
for {\bf $[[:<:]]$} and {\bf $[[:>:]]$} respectively;
no other escapes are available.
-
\subsection{Regular Expression Character Names}\label{wxresynchars}
\helpref{Syntax of the builtin regular expression library}{wxresyn}
\twocolitem{backslash}{'$\backslash$'}
\twocolitem{reverse-solidus}{'$\backslash$'}
\twocolitem{right-square-bracket}{'$]$'}
-\twocolitem{circumflex}{'$^$'}
-\twocolitem{circumflex-accent}{'$^$'}
+\twocolitem{circumflex}{'\caret'}
+\twocolitem{circumflex-accent}{'\caret'}
\twocolitem{underscore}{'\_'}
\twocolitem{low-line}{'\_'}
\twocolitem{grave-accent}{'`'}
\twocolitem{vertical-line}{'$|$'}
\twocolitem{right-brace}{'\}'}
\twocolitem{right-curly-bracket}{'\}'}
-\twocolitem{tilde}{'$~$'}
+\twocolitem{tilde}{'\destruct{}'}
\twocolitem{DEL}{'$\backslash$177'}
\end{twocollist}
+
projects / wxWidgets.git / blobdiff