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
     NULL for the "i"th argument, or pass fewer arguments than
     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]+(\\d+)?", &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) 2006 Google Inc.
.fi
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 06 March 2007
.fi
1	.TH PCRECPP 3
2	.SH NAME
3	PCRE - Perl-compatible regular expressions.
4	.SH "SYNOPSIS OF C++ WRAPPER"
5	.rs
6	.sp
7	.B #include <pcrecpp.h>
8	.
9	.SH DESCRIPTION
10	.rs
11	.sp
12	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	.
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	NULL for the "i"th argument, or pass fewer arguments than
83	number of sub-patterns, "i"th captured sub-pattern is
84	ignored.
85	.sp
86	CAVEAT: An optional sub-pattern that does not exist in the matched
87	string is assigned the empty string. Therefore, the following will
88	return false (because the empty string is not a valid number):
89	.sp
90	int number;
91	pcrecpp::RE::FullMatch("abc", "[a-z]+(\\d+)?", &number);
92	.sp
93	The matching interface supports at most 16 arguments per call.
94	If you need more, consider using the more general interface
95	\fBpcrecpp::RE::DoMatch\fP. See \fBpcrecpp.h\fP for the signature for
96	\fBDoMatch\fP.
97	.
98	.SH "QUOTING METACHARACTERS"
99	.rs
100	.sp
101	You can use the "QuoteMeta" operation to insert backslashes before all
102	potentially meaningful characters in a string. The returned string, used as a
103	regular expression, will exactly match the original string.
104	.sp
105	Example:
106	string quoted = RE::QuoteMeta(unquoted);
107	.sp
108	Note that it's legal to escape a character even if it has no special meaning in
109	a regular expression -- so this function does that. (This also makes it
110	identical to the perl function of the same name; see "perldoc -f quotemeta".)
111	For example, "1.5-2.0?" becomes "1\e.5\e-2\e.0\e?".
112	.
113	.SH "PARTIAL MATCHES"
114	.rs
115	.sp
116	You can use the "PartialMatch" operation when you want the pattern
117	to match any substring of the text.
118	.sp
119	Example: simple search for a string:
120	pcrecpp::RE("ell").PartialMatch("hello");
121	.sp
122	Example: find first number in a string:
123	int number;
124	pcrecpp::RE re("(\e\ed+)");
125	re.PartialMatch("x*100 + 20", &number);
126	assert(number == 100);
127	.
128	.
129	.SH "UTF-8 AND THE MATCHING INTERFACE"
130	.rs
131	.sp
132	By default, pattern and text are plain text, one byte per character. The UTF8
133	flag, passed to the constructor, causes both pattern and string to be treated
134	as UTF-8 text, still a byte stream but potentially multiple bytes per
135	character. In practice, the text is likelier to be UTF-8 than the pattern, but
136	the match returned may depend on the UTF8 flag, so always use it when matching
137	UTF8 text. For example, "." will match one byte normally but with UTF8 set may
138	match up to three bytes of a multi-byte character.
139	.sp
140	Example:
141	pcrecpp::RE_Options options;
142	options.set_utf8();
143	pcrecpp::RE re(utf8_pattern, options);
144	re.FullMatch(utf8_string);
145	.sp
146	Example: using the convenience function UTF8():
147	pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8());
148	re.FullMatch(utf8_string);
149	.sp
150	NOTE: The UTF8 flag is ignored if pcre was not configured with the
151	--enable-utf8 flag.
152	.
153	.
154	.SH "PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE"
155	.rs
156	.sp
157	PCRE defines some modifiers to change the behavior of the regular expression
158	engine. The C++ wrapper defines an auxiliary class, RE_Options, as a vehicle to
159	pass such modifiers to a RE class. Currently, the following modifiers are
160	supported:
161	.sp
162	modifier description Perl corresponding
163	.sp
164	PCRE_CASELESS case insensitive match /i
165	PCRE_MULTILINE multiple lines match /m
166	PCRE_DOTALL dot matches newlines /s
167	PCRE_DOLLAR_ENDONLY $ matches only at end N/A
168	PCRE_EXTRA strict escape parsing N/A
169	PCRE_EXTENDED ignore whitespaces /x
170	PCRE_UTF8 handles UTF8 chars built-in
171	PCRE_UNGREEDY reverses * and *? N/A
172	PCRE_NO_AUTO_CAPTURE disables capturing parens N/A (*)
173	.sp
174	(*) Both Perl and PCRE allow non capturing parentheses by means of the
175	"?:" modifier within the pattern itself. e.g. (?:ab\|cd) does not
176	capture, while (ab\|cd) does.
177	.P
178	For a full account on how each modifier works, please check the
179	PCRE API reference page.
180	.P
181	For each modifier, there are two member functions whose name is made
182	out of the modifier in lowercase, without the "PCRE_" prefix. For
183	instance, PCRE_CASELESS is handled by
184	.sp
185	bool caseless()
186	.sp
187	which returns true if the modifier is set, and
188	.sp
189	RE_Options & set_caseless(bool)
190	.sp
191	which sets or unsets the modifier. Moreover, PCRE_EXTRA_MATCH_LIMIT can be
192	accessed through the \fBset_match_limit()\fR and \fBmatch_limit()\fR member
193	functions. Setting \fImatch_limit\fR to a non-zero value will limit the
194	execution of pcre to keep it from doing bad things like blowing the stack or
195	taking an eternity to return a result. A value of 5000 is good enough to stop
196	stack blowup in a 2MB thread stack. Setting \fImatch_limit\fR to zero disables
197	match limiting. Alternatively, you can call \fBmatch_limit_recursion()\fP
198	which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to limit how much PCRE
199	recurses. \fBmatch_limit()\fP limits the number of matches PCRE does;
200	\fBmatch_limit_recursion()\fP limits the depth of internal recursion, and
201	therefore the amount of stack that is used.
202	.P
203	Normally, to pass one or more modifiers to a RE class, you declare
204	a \fIRE_Options\fR object, set the appropriate options, and pass this
205	object to a RE constructor. Example:
206	.sp
207	RE_options opt;
208	opt.set_caseless(true);
209	if (RE("HELLO", opt).PartialMatch("hello world")) ...
210	.sp
211	RE_options has two constructors. The default constructor takes no arguments and
212	creates a set of flags that are off by default. The optional parameter
213	\fIoption_flags\fR is to facilitate transfer of legacy code from C programs.
214	This lets you do
215	.sp
216	RE(pattern,
217	RE_Options(PCRE_CASELESS\|PCRE_MULTILINE)).PartialMatch(str);
218	.sp
219	However, new code is better off doing
220	.sp
221	RE(pattern,
222	RE_Options().set_caseless(true).set_multiline(true))
223	.PartialMatch(str);
224	.sp
225	If you are going to pass one of the most used modifiers, there are some
226	convenience functions that return a RE_Options class with the
227	appropriate modifier already set: \fBCASELESS()\fR, \fBUTF8()\fR,
228	\fBMULTILINE()\fR, \fBDOTALL\fR(), and \fBEXTENDED()\fR.
229	.P
230	If you need to set several options at once, and you don't want to go through
231	the pains of declaring a RE_Options object and setting several options, there
232	is a parallel method that give you such ability on the fly. You can concatenate
233	several \fBset_xxxxx()\fR member functions, since each of them returns a
234	reference to its class object. For example, to pass PCRE_CASELESS,
235	PCRE_EXTENDED, and PCRE_MULTILINE to a RE with one statement, you may write:
236	.sp
237	RE(" ^ xyz \e\es+ .* blah$",
238	RE_Options()
239	.set_caseless(true)
240	.set_extended(true)
241	.set_multiline(true)).PartialMatch(sometext);
242	.sp
243	.
244	.
245	.SH "SCANNING TEXT INCREMENTALLY"
246	.rs
247	.sp
248	The "Consume" operation may be useful if you want to repeatedly
249	match regular expressions at the front of a string and skip over
250	them as they match. This requires use of the "StringPiece" type,
251	which represents a sub-range of a real string. Like RE, StringPiece
252	is defined in the pcrecpp namespace.
253	.sp
254	Example: read lines of the form "var = value" from a string.
255	string contents = ...; // Fill string somehow
256	pcrecpp::StringPiece input(contents); // Wrap in a StringPiece
257
258	string var;
259	int value;
260	pcrecpp::RE re("(\e\ew+) = (\e\ed+)\en");
261	while (re.Consume(&input, &var, &value)) {
262	...;
263	}
264	.sp
265	Each successful call to "Consume" will set "var/value", and also
266	advance "input" so it points past the matched text.
267	.P
268	The "FindAndConsume" operation is similar to "Consume" but does not
269	anchor your match at the beginning of the string. For example, you
270	could extract all words from a string by repeatedly calling
271	.sp
272	pcrecpp::RE("(\e\ew+)").FindAndConsume(&input, &word)
273	.
274	.
275	.SH "PARSING HEX/OCTAL/C-RADIX NUMBERS"
276	.rs
277	.sp
278	By default, if you pass a pointer to a numeric value, the
279	corresponding text is interpreted as a base-10 number. You can
280	instead wrap the pointer with a call to one of the operators Hex(),
281	Octal(), or CRadix() to interpret the text in another base. The
282	CRadix operator interprets C-style "0" (base-8) and "0x" (base-16)
283	prefixes, but defaults to base-10.
284	.sp
285	Example:
286	int a, b, c, d;
287	pcrecpp::RE re("(.) (.) (.) (.)");
288	re.FullMatch("100 40 0100 0x40",
289	pcrecpp::Octal(&a), pcrecpp::Hex(&b),
290	pcrecpp::CRadix(&c), pcrecpp::CRadix(&d));
291	.sp
292	will leave 64 in a, b, c, and d.
293	.
294	.
295	.SH "REPLACING PARTS OF STRINGS"
296	.rs
297	.sp
298	You can replace the first match of "pattern" in "str" with "rewrite".
299	Within "rewrite", backslash-escaped digits (\e1 to \e9) can be
300	used to insert text matching corresponding parenthesized group
301	from the pattern. \e0 in "rewrite" refers to the entire matching
302	text. For example:
303	.sp
304	string s = "yabba dabba doo";
305	pcrecpp::RE("b+").Replace("d", &s);
306	.sp
307	will leave "s" containing "yada dabba doo". The result is true if the pattern
308	matches and a replacement occurs, false otherwise.
309	.P
310	\fBGlobalReplace\fP is like \fBReplace\fP except that it replaces all
311	occurrences of the pattern in the string with the rewrite. Replacements are
312	not subject to re-matching. For example:
313	.sp
314	string s = "yabba dabba doo";
315	pcrecpp::RE("b+").GlobalReplace("d", &s);
316	.sp
317	will leave "s" containing "yada dada doo". It returns the number of
318	replacements made.
319	.P
320	\fBExtract\fP is like \fBReplace\fP, except that if the pattern matches,
321	"rewrite" is copied into "out" (an additional argument) with substitutions.
322	The non-matching portions of "text" are ignored. Returns true iff a match
323	occurred and the extraction happened successfully; if no match occurs, the
324	string is left unaffected.
325	.
326	.
327	.SH AUTHOR
328	.rs
329	.sp
330	.nf
331	The C++ wrapper was contributed by Google Inc.
332	Copyright (c) 2006 Google Inc.
333	.fi
334	.
335	.
336	.SH REVISION
337	.rs
338	.sp
339	.nf
340	Last updated: 06 March 2007
341	.fi
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