wxRegEx represents a regular expression. The regular expressions syntax supported is the POSIX one. Both basic and extended regular expressions are supported but, unlike POSIX C API, the extended ones are used by default.
This class provides support for regular expressions matching and also replacement. It is built on top of either the system library (if it has support for POSIX regular expressions - which is the case of the most modern Unices) or uses the built in Henry Spencer's library. In the latter case you need to abide by the terms of its copyright:
Copyright 1992, 1993, 1994, 1997 Henry Spencer. All rights reserved. This software is not subject to any license of the American Telephone and Telegraph Company or of the Regents of the University of California. Permission is granted to anyone to use this software for any purpose on any computer system, and to alter it and redistribute it, subject to the following restrictions: 1. The author is not responsible for the consequences of use of this software, no matter how awful, even if they arise from flaws in it. 2. The origin of this software must not be misrepresented, either by explicit claim or by omission. Since few users ever read sources, credits must appear in the documentation. 3. Altered versions must be plainly marked as such, and must not be misrepresented as being the original software. Since few users ever read sources, credits must appear in the documentation. 4. This notice may not be removed or altered.Derived from
No base class
Data structures
Flags for regex compilation to be used with Compile():
enum { // use extended regex syntax (default) wxRE_EXTENDED = 0, // use basic RE syntax wxRE_BASIC = 2, // ignore case in match wxRE_ICASE = 4, // only check match, don't set back references wxRE_NOSUB = 8, // if not set, treat '\n' as an ordinary character, otherwise it is // special: it is not matched by '.' and '^' and '$' always match // after/before it regardless of the setting of wxRE_NOT[BE]OL wxRE_NEWLINE = 16, // default flags wxRE_DEFAULT = wxRE_EXTENDED }Flags for regex matching to be used with Matches().
These flags are mainly useful when doing several matches in a long string to prevent erroneous matches for '' and '$':
enum { // '^' doesn't match at the start of line wxRE_NOTBOL = 32, // '$' doesn't match at the end of line wxRE_NOTEOL = 64 }Examples
A bad example of processing some text containing email addresses (the example is bad because the real email addresses can have more complicated form than user@host.net):
wxString text; ... wxRegEx reEmail = "([^@]+)@([[:alnum:].-_].)+([[:alnum:]]+)"; if ( reEmail.Matches(text) ) { wxString text = reEmail.GetMatch(email); wxString username = reEmail.GetMatch(email, 1); if ( reEmail.GetMatch(email, 3) == "com" ) // .com TLD? { ... } } // or we could do this to hide the email address size_t count = reEmail.ReplaceAll(text, "HIDDEN@\\2\\3"); printf("text now contains %u hidden addresses", count);Members
wxRegEx::wxRegEx
wxRegEx::~wxRegEx
wxRegEx::Compile
wxRegEx::IsValid
wxRegEx::GetMatch
wxRegEx::Matches
wxRegEx::Replace
wxRegEx::ReplaceAll
wxRegEx::ReplaceFirst
wxRegEx()
Default ctor: use Compile() later.
wxRegEx(const wxString& expr, int flags = wxRE_DEFAULT)
Create and compile the regular expression, use IsValid to test for compilation errors.
~wxRegEx()
dtor not virtual, don't derive from this class
bool Compile(const wxString& pattern, int flags = wxRE_DEFAULT)
Compile the string into regular expression, return TRUE if ok or FALSE if string has a syntax error.
bool IsValid() const
Return TRUE if this is a valid compiled regular expression, FALSE otherwise.
bool GetMatch(size_t* start, size_t* len, size_t index = 0) const
Get the start index and the length of the match of the expression (if index is 0) or a bracketed subexpression (index different from 0).
May only be called after successful call to Matches() and only if wxRE_NOSUB was not used in Compile().
Returns FALSE if no match or if an error occured.
wxString GetMatch(const wxString& text, size_t index = 0) const
Returns the part of string corresponding to the match where index is interpreted as above. Empty string is returned if match failed
May only be called after successful call to Matches() and only if wxRE_NOSUB was not used in Compile().
bool Matches(const wxChar* text, int flags = 0) const
Matches the precompiled regular expression against the string text, returns TRUE if matches and FALSE otherwise.
Flags may be combination of wxRE_NOTBOL and wxRE_NOTEOL.
May only be called after successful call to Compile().
int Replace(wxString* text, const wxString& replacement, size_t maxMatches = 0) const
Replaces the current regular expression in the string pointed to by text, with the text in replacement and return number of matches replaced (maybe 0 if none found) or -1 on error.
The replacement text may contain back references \number which will be replaced with the value of the corresponding subexpression in the pattern match. \0 corresponds to the entire match and & is a synonym for it. Backslash may be used to quote itself or & character.
maxMatches may be used to limit the number of replacements made, setting it to 1, for example, will only replace first occurrence (if any) of the pattern in the text while default value of 0 means replace all.
int ReplaceAll(wxString* text, const wxString& replacement) const
Replace all occurrences: this is actually a synonym for Replace().
See also
int ReplaceFirst(wxString* text, const wxString& replacement) const
Replace the first occurrence.
See also