trunk/doc/pcrecpp.3

.TH PCRECPP 3
.SH NAME
PCRE - Perl-compatible regular expressions.
.SH "SYNOPSIS OF C++ WRAPPER"
.rs
.sp
.B #include <pcrecpp.h>
.
.SH DESCRIPTION
.rs
.sp
The C++ wrapper for PCRE was provided by Google Inc. Some additional
functionality was added by Giuseppe Maxia. This brief man page was constructed
from the notes in the \fIpcrecpp.h\fP file, which should be consulted for
further details.
.
.
.SH "MATCHING INTERFACE"
.rs
.sp
The "FullMatch" operation checks that supplied text matches a supplied pattern
exactly. If pointer arguments are supplied, it copies matched sub-strings that
match sub-patterns into them.
.sp
  Example: successful match
     pcrecpp::RE re("h.*o");
     re.FullMatch("hello");
.sp
  Example: unsuccessful match (requires full match):
     pcrecpp::RE re("e");
     !re.FullMatch("hello");
.sp
  Example: creating a temporary RE object:
     pcrecpp::RE("h.*o").FullMatch("hello");
.sp
You can pass in a "const char*" or a "string" for "text". The examples below
tend to use a const char*. You can, as in the different examples above, store
the RE object explicitly in a variable or use a temporary RE object. The
examples below use one mode or the other arbitrarily. Either could correctly be
used for any of these examples.
.P
You must supply extra pointer arguments to extract matched subpieces.
.sp
  Example: extracts "ruby" into "s" and 1234 into "i"
     int i;
     string s;
     pcrecpp::RE re("(\e\ew+):(\e\ed+)");
     re.FullMatch("ruby:1234", &s, &i);
.sp
  Example: does not try to extract any extra sub-patterns
     re.FullMatch("ruby:1234", &s);
.sp
  Example: does not try to extract into NULL
     re.FullMatch("ruby:1234", NULL, &i);
.sp
  Example: integer overflow causes failure
     !re.FullMatch("ruby:1234567891234", NULL, &i);
.sp
  Example: fails because there aren't enough sub-patterns:
     !pcrecpp::RE("\e\ew+:\e\ed+").FullMatch("ruby:1234", &s);
.sp
  Example: fails because string cannot be stored in integer
     !pcrecpp::RE("(.*)").FullMatch("ruby", &i);
.sp
The provided pointer arguments can be pointers to any scalar numeric
type, or one of:
.sp
   string        (matched piece is copied to string)
   StringPiece   (StringPiece is mutated to point to matched piece)
   T             (where "bool T::ParseFrom(const char*, int)" exists)
   NULL          (the corresponding matched sub-pattern is not copied)
.sp
The function returns true iff all of the following conditions are satisfied:
.sp
  a. "text" matches "pattern" exactly;
.sp
  b. The number of matched sub-patterns is >= number of supplied
     pointers;
.sp
  c. The "i"th argument has a suitable type for holding the
     string captured as the "i"th sub-pattern. If you pass in
     void * NULL for the "i"th argument, or a non-void * NULL
     of the correct type, or pass fewer arguments than the
     number of sub-patterns, "i"th captured sub-pattern is
     ignored.
.sp
CAVEAT: An optional sub-pattern that does not exist in the matched
string is assigned the empty string. Therefore, the following will
return false (because the empty string is not a valid number):
.sp
   int number;
   pcrecpp::RE::FullMatch("abc", "[a-z]+(\e\ed+)?", &number);
.sp
The matching interface supports at most 16 arguments per call.
If you need more, consider using the more general interface
\fBpcrecpp::RE::DoMatch\fP. See \fBpcrecpp.h\fP for the signature for
\fBDoMatch\fP.
.
.SH "QUOTING METACHARACTERS"
.rs
.sp
You can use the "QuoteMeta" operation to insert backslashes before all
potentially meaningful characters in a string. The returned string, used as a
regular expression, will exactly match the original string.
.sp
  Example:
     string quoted = RE::QuoteMeta(unquoted);
.sp
Note that it's legal to escape a character even if it has no special meaning in
a regular expression -- so this function does that. (This also makes it
identical to the perl function of the same name; see "perldoc -f quotemeta".)
For example, "1.5-2.0?" becomes "1\e.5\e-2\e.0\e?".
.
.SH "PARTIAL MATCHES"
.rs
.sp
You can use the "PartialMatch" operation when you want the pattern
to match any substring of the text.
.sp
  Example: simple search for a string:
     pcrecpp::RE("ell").PartialMatch("hello");
.sp
  Example: find first number in a string:
     int number;
     pcrecpp::RE re("(\e\ed+)");
     re.PartialMatch("x*100 + 20", &number);
     assert(number == 100);
.
.
.SH "UTF-8 AND THE MATCHING INTERFACE"
.rs
.sp
By default, pattern and text are plain text, one byte per character. The UTF8
flag, passed to the constructor, causes both pattern and string to be treated
as UTF-8 text, still a byte stream but potentially multiple bytes per
character. In practice, the text is likelier to be UTF-8 than the pattern, but
the match returned may depend on the UTF8 flag, so always use it when matching
UTF8 text. For example, "." will match one byte normally but with UTF8 set may
match up to three bytes of a multi-byte character.
.sp
  Example:
     pcrecpp::RE_Options options;
     options.set_utf8();
     pcrecpp::RE re(utf8_pattern, options);
     re.FullMatch(utf8_string);
.sp
  Example: using the convenience function UTF8():
     pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8());
     re.FullMatch(utf8_string);
.sp
NOTE: The UTF8 flag is ignored if pcre was not configured with the
      --enable-utf8 flag.
.
.
.SH "PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE"
.rs
.sp
PCRE defines some modifiers to change the behavior of the regular expression
engine. The C++ wrapper defines an auxiliary class, RE_Options, as a vehicle to
pass such modifiers to a RE class. Currently, the following modifiers are
supported:
.sp
   modifier              description               Perl corresponding
.sp
   PCRE_CASELESS         case insensitive match      /i
   PCRE_MULTILINE        multiple lines match        /m
   PCRE_DOTALL           dot matches newlines        /s
   PCRE_DOLLAR_ENDONLY   $ matches only at end       N/A
   PCRE_EXTRA            strict escape parsing       N/A
   PCRE_EXTENDED         ignore whitespaces          /x
   PCRE_UTF8             handles UTF8 chars          built-in
   PCRE_UNGREEDY         reverses * and *?           N/A
   PCRE_NO_AUTO_CAPTURE  disables capturing parens   N/A (*)
.sp
(*) Both Perl and PCRE allow non capturing parentheses by means of the
"?:" modifier within the pattern itself. e.g. (?:ab|cd) does not
capture, while (ab|cd) does.
.P
For a full account on how each modifier works, please check the
PCRE API reference page.
.P
For each modifier, there are two member functions whose name is made
out of the modifier in lowercase, without the "PCRE_" prefix. For
instance, PCRE_CASELESS is handled by
.sp
  bool caseless()
.sp
which returns true if the modifier is set, and
.sp
  RE_Options & set_caseless(bool)
.sp
which sets or unsets the modifier. Moreover, PCRE_EXTRA_MATCH_LIMIT can be
accessed through the \fBset_match_limit()\fR and \fBmatch_limit()\fR member
functions. Setting \fImatch_limit\fR to a non-zero value will limit the
execution of pcre to keep it from doing bad things like blowing the stack or
taking an eternity to return a result. A value of 5000 is good enough to stop
stack blowup in a 2MB thread stack. Setting \fImatch_limit\fR to zero disables
match limiting. Alternatively, you can call \fBmatch_limit_recursion()\fP
which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to limit how much PCRE
recurses. \fBmatch_limit()\fP limits the number of matches PCRE does;
\fBmatch_limit_recursion()\fP limits the depth of internal recursion, and
therefore the amount of stack that is used.
.P
Normally, to pass one or more modifiers to a RE class, you declare
a \fIRE_Options\fR object, set the appropriate options, and pass this
object to a RE constructor. Example:
.sp
   RE_options opt;
   opt.set_caseless(true);
   if (RE("HELLO", opt).PartialMatch("hello world")) ...
.sp
RE_options has two constructors. The default constructor takes no arguments and
creates a set of flags that are off by default. The optional parameter
\fIoption_flags\fR is to facilitate transfer of legacy code from C programs.
This lets you do
.sp
   RE(pattern,
     RE_Options(PCRE_CASELESS|PCRE_MULTILINE)).PartialMatch(str);
.sp
However, new code is better off doing
.sp
   RE(pattern,
     RE_Options().set_caseless(true).set_multiline(true))
       .PartialMatch(str);
.sp
If you are going to pass one of the most used modifiers, there are some
convenience functions that return a RE_Options class with the
appropriate modifier already set: \fBCASELESS()\fR, \fBUTF8()\fR,
\fBMULTILINE()\fR, \fBDOTALL\fR(), and \fBEXTENDED()\fR.
.P
If you need to set several options at once, and you don't want to go through
the pains of declaring a RE_Options object and setting several options, there
is a parallel method that give you such ability on the fly. You can concatenate
several \fBset_xxxxx()\fR member functions, since each of them returns a
reference to its class object. For example, to pass PCRE_CASELESS,
PCRE_EXTENDED, and PCRE_MULTILINE to a RE with one statement, you may write:
.sp
   RE(" ^ xyz \e\es+ .* blah$",
     RE_Options()
       .set_caseless(true)
       .set_extended(true)
       .set_multiline(true)).PartialMatch(sometext);
.sp
.
.
.SH "SCANNING TEXT INCREMENTALLY"
.rs
.sp
The "Consume" operation may be useful if you want to repeatedly
match regular expressions at the front of a string and skip over
them as they match. This requires use of the "StringPiece" type,
which represents a sub-range of a real string. Like RE, StringPiece
is defined in the pcrecpp namespace.
.sp
  Example: read lines of the form "var = value" from a string.
     string contents = ...;                 // Fill string somehow
     pcrecpp::StringPiece input(contents);  // Wrap in a StringPiece

     string var;
     int value;
     pcrecpp::RE re("(\e\ew+) = (\e\ed+)\en");
     while (re.Consume(&input, &var, &value)) {
       ...;
     }
.sp
Each successful call to "Consume" will set "var/value", and also
advance "input" so it points past the matched text.
.P
The "FindAndConsume" operation is similar to "Consume" but does not
anchor your match at the beginning of the string. For example, you
could extract all words from a string by repeatedly calling
.sp
  pcrecpp::RE("(\e\ew+)").FindAndConsume(&input, &word)
.
.
.SH "PARSING HEX/OCTAL/C-RADIX NUMBERS"
.rs
.sp
By default, if you pass a pointer to a numeric value, the
corresponding text is interpreted as a base-10 number. You can
instead wrap the pointer with a call to one of the operators Hex(),
Octal(), or CRadix() to interpret the text in another base. The
CRadix operator interprets C-style "0" (base-8) and "0x" (base-16)
prefixes, but defaults to base-10.
.sp
  Example:
    int a, b, c, d;
    pcrecpp::RE re("(.*) (.*) (.*) (.*)");
    re.FullMatch("100 40 0100 0x40",
                 pcrecpp::Octal(&a), pcrecpp::Hex(&b),
                 pcrecpp::CRadix(&c), pcrecpp::CRadix(&d));
.sp
will leave 64 in a, b, c, and d.
.
.
.SH "REPLACING PARTS OF STRINGS"
.rs
.sp
You can replace the first match of "pattern" in "str" with "rewrite".
Within "rewrite", backslash-escaped digits (\e1 to \e9) can be
used to insert text matching corresponding parenthesized group
from the pattern. \e0 in "rewrite" refers to the entire matching
text. For example:
.sp
  string s = "yabba dabba doo";
  pcrecpp::RE("b+").Replace("d", &s);
.sp
will leave "s" containing "yada dabba doo". The result is true if the pattern
matches and a replacement occurs, false otherwise.
.P
\fBGlobalReplace\fP is like \fBReplace\fP except that it replaces all
occurrences of the pattern in the string with the rewrite. Replacements are
not subject to re-matching. For example:
.sp
  string s = "yabba dabba doo";
  pcrecpp::RE("b+").GlobalReplace("d", &s);
.sp
will leave "s" containing "yada dada doo". It returns the number of
replacements made.
.P
\fBExtract\fP is like \fBReplace\fP, except that if the pattern matches,
"rewrite" is copied into "out" (an additional argument) with substitutions.
The non-matching portions of "text" are ignored. Returns true iff a match
occurred and the extraction happened successfully;  if no match occurs, the
string is left unaffected.
.
.
.SH AUTHOR
.rs
.sp
.nf
The C++ wrapper was contributed by Google Inc.
Copyright (c) 2007 Google Inc.
.fi
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 12 November 2007
.fi
1	nigel	79	.TH PCRECPP 3
2	nigel	77	.SH NAME
3			PCRE - Perl-compatible regular expressions.
4			.SH "SYNOPSIS OF C++ WRAPPER"
5			.rs
6			.sp
7			.B #include <pcrecpp.h>
8	ph10	99	.
9	nigel	77	.SH DESCRIPTION
10			.rs
11			.sp
12	nigel	81	The C++ wrapper for PCRE was provided by Google Inc. Some additional
13			functionality was added by Giuseppe Maxia. This brief man page was constructed
14			from the notes in the \fIpcrecpp.h\fP file, which should be consulted for
15			further details.
16	nigel	77	.
17			.
18			.SH "MATCHING INTERFACE"
19			.rs
20			.sp
21			The "FullMatch" operation checks that supplied text matches a supplied pattern
22			exactly. If pointer arguments are supplied, it copies matched sub-strings that
23			match sub-patterns into them.
24			.sp
25			Example: successful match
26			pcrecpp::RE re("h.*o");
27			re.FullMatch("hello");
28			.sp
29			Example: unsuccessful match (requires full match):
30			pcrecpp::RE re("e");
31			!re.FullMatch("hello");
32			.sp
33			Example: creating a temporary RE object:
34			pcrecpp::RE("h.*o").FullMatch("hello");
35			.sp
36			You can pass in a "const char*" or a "string" for "text". The examples below
37			tend to use a const char*. You can, as in the different examples above, store
38			the RE object explicitly in a variable or use a temporary RE object. The
39			examples below use one mode or the other arbitrarily. Either could correctly be
40			used for any of these examples.
41			.P
42			You must supply extra pointer arguments to extract matched subpieces.
43			.sp
44			Example: extracts "ruby" into "s" and 1234 into "i"
45			int i;
46			string s;
47			pcrecpp::RE re("(\e\ew+):(\e\ed+)");
48			re.FullMatch("ruby:1234", &s, &i);
49			.sp
50			Example: does not try to extract any extra sub-patterns
51			re.FullMatch("ruby:1234", &s);
52			.sp
53			Example: does not try to extract into NULL
54			re.FullMatch("ruby:1234", NULL, &i);
55			.sp
56			Example: integer overflow causes failure
57			!re.FullMatch("ruby:1234567891234", NULL, &i);
58			.sp
59			Example: fails because there aren't enough sub-patterns:
60			!pcrecpp::RE("\e\ew+:\e\ed+").FullMatch("ruby:1234", &s);
61			.sp
62			Example: fails because string cannot be stored in integer
63			!pcrecpp::RE("(.*)").FullMatch("ruby", &i);
64			.sp
65			The provided pointer arguments can be pointers to any scalar numeric
66			type, or one of:
67			.sp
68			string (matched piece is copied to string)
69			StringPiece (StringPiece is mutated to point to matched piece)
70			T (where "bool T::ParseFrom(const char*, int)" exists)
71			NULL (the corresponding matched sub-pattern is not copied)
72			.sp
73			The function returns true iff all of the following conditions are satisfied:
74			.sp
75			a. "text" matches "pattern" exactly;
76			.sp
77			b. The number of matched sub-patterns is >= number of supplied
78			pointers;
79			.sp
80			c. The "i"th argument has a suitable type for holding the
81			string captured as the "i"th sub-pattern. If you pass in
82	ph10	263	void * NULL for the "i"th argument, or a non-void * NULL
83	ph10	286	of the correct type, or pass fewer arguments than the
84	nigel	77	number of sub-patterns, "i"th captured sub-pattern is
85			ignored.
86			.sp
87	nigel	93	CAVEAT: An optional sub-pattern that does not exist in the matched
88			string is assigned the empty string. Therefore, the following will
89			return false (because the empty string is not a valid number):
90			.sp
91			int number;
92	ph10	155	pcrecpp::RE::FullMatch("abc", "[a-z]+(\e\ed+)?", &number);
93	nigel	93	.sp
94	nigel	77	The matching interface supports at most 16 arguments per call.
95			If you need more, consider using the more general interface
96			\fBpcrecpp::RE::DoMatch\fP. See \fBpcrecpp.h\fP for the signature for
97			\fBDoMatch\fP.
98			.
99	nigel	93	.SH "QUOTING METACHARACTERS"
100			.rs
101			.sp
102			You can use the "QuoteMeta" operation to insert backslashes before all
103			potentially meaningful characters in a string. The returned string, used as a
104			regular expression, will exactly match the original string.
105			.sp
106			Example:
107			string quoted = RE::QuoteMeta(unquoted);
108			.sp
109			Note that it's legal to escape a character even if it has no special meaning in
110			a regular expression -- so this function does that. (This also makes it
111			identical to the perl function of the same name; see "perldoc -f quotemeta".)
112			For example, "1.5-2.0?" becomes "1\e.5\e-2\e.0\e?".
113			.
114	nigel	77	.SH "PARTIAL MATCHES"
115			.rs
116			.sp
117			You can use the "PartialMatch" operation when you want the pattern
118			to match any substring of the text.
119			.sp
120			Example: simple search for a string:
121			pcrecpp::RE("ell").PartialMatch("hello");
122			.sp
123			Example: find first number in a string:
124			int number;
125			pcrecpp::RE re("(\e\ed+)");
126			re.PartialMatch("x*100 + 20", &number);
127			assert(number == 100);
128			.
129			.
130			.SH "UTF-8 AND THE MATCHING INTERFACE"
131			.rs
132			.sp
133			By default, pattern and text are plain text, one byte per character. The UTF8
134			flag, passed to the constructor, causes both pattern and string to be treated
135			as UTF-8 text, still a byte stream but potentially multiple bytes per
136			character. In practice, the text is likelier to be UTF-8 than the pattern, but
137			the match returned may depend on the UTF8 flag, so always use it when matching
138			UTF8 text. For example, "." will match one byte normally but with UTF8 set may
139			match up to three bytes of a multi-byte character.
140			.sp
141			Example:
142			pcrecpp::RE_Options options;
143			options.set_utf8();
144			pcrecpp::RE re(utf8_pattern, options);
145			re.FullMatch(utf8_string);
146			.sp
147			Example: using the convenience function UTF8():
148			pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8());
149			re.FullMatch(utf8_string);
150			.sp
151			NOTE: The UTF8 flag is ignored if pcre was not configured with the
152			--enable-utf8 flag.
153			.
154			.
155	nigel	81	.SH "PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE"
156			.rs
157			.sp
158			PCRE defines some modifiers to change the behavior of the regular expression
159			engine. The C++ wrapper defines an auxiliary class, RE_Options, as a vehicle to
160			pass such modifiers to a RE class. Currently, the following modifiers are
161			supported:
162			.sp
163			modifier description Perl corresponding
164			.sp
165			PCRE_CASELESS case insensitive match /i
166			PCRE_MULTILINE multiple lines match /m
167			PCRE_DOTALL dot matches newlines /s
168			PCRE_DOLLAR_ENDONLY $ matches only at end N/A
169			PCRE_EXTRA strict escape parsing N/A
170			PCRE_EXTENDED ignore whitespaces /x
171			PCRE_UTF8 handles UTF8 chars built-in
172			PCRE_UNGREEDY reverses * and *? N/A
173			PCRE_NO_AUTO_CAPTURE disables capturing parens N/A (*)
174			.sp
175			(*) Both Perl and PCRE allow non capturing parentheses by means of the
176			"?:" modifier within the pattern itself. e.g. (?:ab\|cd) does not
177			capture, while (ab\|cd) does.
178			.P
179			For a full account on how each modifier works, please check the
180			PCRE API reference page.
181			.P
182			For each modifier, there are two member functions whose name is made
183			out of the modifier in lowercase, without the "PCRE_" prefix. For
184			instance, PCRE_CASELESS is handled by
185			.sp
186			bool caseless()
187			.sp
188			which returns true if the modifier is set, and
189			.sp
190			RE_Options & set_caseless(bool)
191			.sp
192	nigel	87	which sets or unsets the modifier. Moreover, PCRE_EXTRA_MATCH_LIMIT can be
193	nigel	81	accessed through the \fBset_match_limit()\fR and \fBmatch_limit()\fR member
194			functions. Setting \fImatch_limit\fR to a non-zero value will limit the
195			execution of pcre to keep it from doing bad things like blowing the stack or
196			taking an eternity to return a result. A value of 5000 is good enough to stop
197			stack blowup in a 2MB thread stack. Setting \fImatch_limit\fR to zero disables
198	nigel	87	match limiting. Alternatively, you can call \fBmatch_limit_recursion()\fP
199			which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to limit how much PCRE
200			recurses. \fBmatch_limit()\fP limits the number of matches PCRE does;
201			\fBmatch_limit_recursion()\fP limits the depth of internal recursion, and
202			therefore the amount of stack that is used.
203	nigel	81	.P
204			Normally, to pass one or more modifiers to a RE class, you declare
205			a \fIRE_Options\fR object, set the appropriate options, and pass this
206			object to a RE constructor. Example:
207			.sp
208			RE_options opt;
209			opt.set_caseless(true);
210			if (RE("HELLO", opt).PartialMatch("hello world")) ...
211			.sp
212			RE_options has two constructors. The default constructor takes no arguments and
213			creates a set of flags that are off by default. The optional parameter
214			\fIoption_flags\fR is to facilitate transfer of legacy code from C programs.
215			This lets you do
216			.sp
217			RE(pattern,
218			RE_Options(PCRE_CASELESS\|PCRE_MULTILINE)).PartialMatch(str);
219			.sp
220			However, new code is better off doing
221			.sp
222			RE(pattern,
223			RE_Options().set_caseless(true).set_multiline(true))
224			.PartialMatch(str);
225			.sp
226			If you are going to pass one of the most used modifiers, there are some
227			convenience functions that return a RE_Options class with the
228			appropriate modifier already set: \fBCASELESS()\fR, \fBUTF8()\fR,
229			\fBMULTILINE()\fR, \fBDOTALL\fR(), and \fBEXTENDED()\fR.
230			.P
231			If you need to set several options at once, and you don't want to go through
232			the pains of declaring a RE_Options object and setting several options, there
233			is a parallel method that give you such ability on the fly. You can concatenate
234			several \fBset_xxxxx()\fR member functions, since each of them returns a
235			reference to its class object. For example, to pass PCRE_CASELESS,
236			PCRE_EXTENDED, and PCRE_MULTILINE to a RE with one statement, you may write:
237			.sp
238			RE(" ^ xyz \e\es+ .* blah$",
239			RE_Options()
240			.set_caseless(true)
241			.set_extended(true)
242			.set_multiline(true)).PartialMatch(sometext);
243			.sp
244			.
245			.
246	nigel	77	.SH "SCANNING TEXT INCREMENTALLY"
247			.rs
248			.sp
249			The "Consume" operation may be useful if you want to repeatedly
250			match regular expressions at the front of a string and skip over
251			them as they match. This requires use of the "StringPiece" type,
252			which represents a sub-range of a real string. Like RE, StringPiece
253			is defined in the pcrecpp namespace.
254			.sp
255			Example: read lines of the form "var = value" from a string.
256			string contents = ...; // Fill string somehow
257			pcrecpp::StringPiece input(contents); // Wrap in a StringPiece
258
259			string var;
260			int value;
261			pcrecpp::RE re("(\e\ew+) = (\e\ed+)\en");
262			while (re.Consume(&input, &var, &value)) {
263			...;
264			}
265			.sp
266			Each successful call to "Consume" will set "var/value", and also
267			advance "input" so it points past the matched text.
268			.P
269			The "FindAndConsume" operation is similar to "Consume" but does not
270			anchor your match at the beginning of the string. For example, you
271			could extract all words from a string by repeatedly calling
272			.sp
273			pcrecpp::RE("(\e\ew+)").FindAndConsume(&input, &word)
274			.
275			.
276			.SH "PARSING HEX/OCTAL/C-RADIX NUMBERS"
277			.rs
278			.sp
279			By default, if you pass a pointer to a numeric value, the
280			corresponding text is interpreted as a base-10 number. You can
281			instead wrap the pointer with a call to one of the operators Hex(),
282			Octal(), or CRadix() to interpret the text in another base. The
283			CRadix operator interprets C-style "0" (base-8) and "0x" (base-16)
284			prefixes, but defaults to base-10.
285			.sp
286			Example:
287			int a, b, c, d;
288			pcrecpp::RE re("(.) (.) (.) (.)");
289			re.FullMatch("100 40 0100 0x40",
290			pcrecpp::Octal(&a), pcrecpp::Hex(&b),
291			pcrecpp::CRadix(&c), pcrecpp::CRadix(&d));
292			.sp
293			will leave 64 in a, b, c, and d.
294			.
295			.
296			.SH "REPLACING PARTS OF STRINGS"
297			.rs
298			.sp
299			You can replace the first match of "pattern" in "str" with "rewrite".
300			Within "rewrite", backslash-escaped digits (\e1 to \e9) can be
301			used to insert text matching corresponding parenthesized group
302			from the pattern. \e0 in "rewrite" refers to the entire matching
303			text. For example:
304			.sp
305			string s = "yabba dabba doo";
306			pcrecpp::RE("b+").Replace("d", &s);
307			.sp
308			will leave "s" containing "yada dabba doo". The result is true if the pattern
309			matches and a replacement occurs, false otherwise.
310			.P
311			\fBGlobalReplace\fP is like \fBReplace\fP except that it replaces all
312			occurrences of the pattern in the string with the rewrite. Replacements are
313			not subject to re-matching. For example:
314			.sp
315			string s = "yabba dabba doo";
316			pcrecpp::RE("b+").GlobalReplace("d", &s);
317			.sp
318			will leave "s" containing "yada dada doo". It returns the number of
319			replacements made.
320			.P
321			\fBExtract\fP is like \fBReplace\fP, except that if the pattern matches,
322			"rewrite" is copied into "out" (an additional argument) with substitutions.
323			The non-matching portions of "text" are ignored. Returns true iff a match
324			occurred and the extraction happened successfully; if no match occurs, the
325			string is left unaffected.
326			.
327			.
328			.SH AUTHOR
329			.rs
330			.sp
331	ph10	99	.nf
332	nigel	77	The C++ wrapper was contributed by Google Inc.
333	ph10	117	Copyright (c) 2007 Google Inc.
334	ph10	99	.fi
335			.
336			.
337			.SH REVISION
338			.rs
339			.sp
340			.nf
341	ph10	263	Last updated: 12 November 2007
342	ph10	99	.fi
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