doc/html/pcrecpp.html

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<head>
<title>pcrecpp specification</title>
</head>
<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
<h1>pcrecpp man page</h1>
<p>
Return to the <a href="index.html">PCRE index page</a>.
</p>
<p>
This page is part of the PCRE HTML documentation. It was generated automatically
from the original man page. If there is any nonsense in it, please consult the
man page, in case the conversion went wrong.
<br>
<ul>
<li><a name="TOC1" href="#SEC1">SYNOPSIS OF C++ WRAPPER</a>
<li><a name="TOC2" href="#SEC2">DESCRIPTION</a>
<li><a name="TOC3" href="#SEC3">MATCHING INTERFACE</a>
<li><a name="TOC4" href="#SEC4">PARTIAL MATCHES</a>
<li><a name="TOC5" href="#SEC5">UTF-8 AND THE MATCHING INTERFACE</a>
<li><a name="TOC6" href="#SEC6">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a>
<li><a name="TOC7" href="#SEC7">SCANNING TEXT INCREMENTALLY</a>
<li><a name="TOC8" href="#SEC8">PARSING HEX/OCTAL/C-RADIX NUMBERS</a>
<li><a name="TOC9" href="#SEC9">REPLACING PARTS OF STRINGS</a>
<li><a name="TOC10" href="#SEC10">AUTHOR</a>
</ul>
<br><a name="SEC1" href="#TOC1">SYNOPSIS OF C++ WRAPPER</a><br>
<P>
<b>#include &#60;pcrecpp.h&#62;</b>
</P>
<P>
</P>
<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
<P>
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 <i>pcrecpp.h</i> file, which should be consulted for
further details.
</P>
<br><a name="SEC3" href="#TOC1">MATCHING INTERFACE</a><br>
<P>
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.
<pre>
  Example: successful match
     pcrecpp::RE re("h.*o");
     re.FullMatch("hello");

  Example: unsuccessful match (requires full match):
     pcrecpp::RE re("e");
     !re.FullMatch("hello");

  Example: creating a temporary RE object:
     pcrecpp::RE("h.*o").FullMatch("hello");
</pre>
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>
<P>
You must supply extra pointer arguments to extract matched subpieces.
<pre>
  Example: extracts "ruby" into "s" and 1234 into "i"
     int i;
     string s;
     pcrecpp::RE re("(\\w+):(\\d+)");
     re.FullMatch("ruby:1234", &s, &i);

  Example: does not try to extract any extra sub-patterns
     re.FullMatch("ruby:1234", &s);

  Example: does not try to extract into NULL
     re.FullMatch("ruby:1234", NULL, &i);

  Example: integer overflow causes failure
     !re.FullMatch("ruby:1234567891234", NULL, &i);

  Example: fails because there aren't enough sub-patterns:
     !pcrecpp::RE("\\w+:\\d+").FullMatch("ruby:1234", &s);

  Example: fails because string cannot be stored in integer
     !pcrecpp::RE("(.*)").FullMatch("ruby", &i);
</pre>
The provided pointer arguments can be pointers to any scalar numeric
type, or one of:
<pre>
   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)
</pre>
The function returns true iff all of the following conditions are satisfied:
<pre>
  a. "text" matches "pattern" exactly;

  b. The number of matched sub-patterns is &#62;= number of supplied
     pointers;

  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.
</pre>
The matching interface supports at most 16 arguments per call.
If you need more, consider using the more general interface
<b>pcrecpp::RE::DoMatch</b>. See <b>pcrecpp.h</b> for the signature for
<b>DoMatch</b>.
</P>
<br><a name="SEC4" href="#TOC1">PARTIAL MATCHES</a><br>
<P>
You can use the "PartialMatch" operation when you want the pattern
to match any substring of the text.
<pre>
  Example: simple search for a string:
     pcrecpp::RE("ell").PartialMatch("hello");

  Example: find first number in a string:
     int number;
     pcrecpp::RE re("(\\d+)");
     re.PartialMatch("x*100 + 20", &number);
     assert(number == 100);
</PRE>
</P>
<br><a name="SEC5" href="#TOC1">UTF-8 AND THE MATCHING INTERFACE</a><br>
<P>
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.
<pre>
  Example:
     pcrecpp::RE_Options options;
     options.set_utf8();
     pcrecpp::RE re(utf8_pattern, options);
     re.FullMatch(utf8_string);

  Example: using the convenience function UTF8():
     pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8());
     re.FullMatch(utf8_string);
</pre>
NOTE: The UTF8 flag is ignored if pcre was not configured with the
<pre>
      --enable-utf8 flag.
</PRE>
</P>
<br><a name="SEC6" href="#TOC1">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a><br>
<P>
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:
<pre>
   modifier              description               Perl corresponding

   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 (*)
</pre>
(*) 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>
<P>
For a full account on how each modifier works, please check the
PCRE API reference page.
</P>
<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
<pre>
  bool caseless()
</pre>
which returns true if the modifier is set, and
<pre>
  RE_Options & set_caseless(bool)
</pre>
which sets or unsets the modifier. Moreover, PCRE_EXTRA_MATCH_LIMIT can be
accessed through the <b>set_match_limit()</b> and <b>match_limit()</b> member
functions. Setting <i>match_limit</i> 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 <i>match_limit</i> to zero disables
match limiting. Alternatively, you can call <b>match_limit_recursion()</b>
which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to limit how much PCRE
recurses. <b>match_limit()</b> limits the number of matches PCRE does;
<b>match_limit_recursion()</b> limits the depth of internal recursion, and
therefore the amount of stack that is used.
</P>
<P>
Normally, to pass one or more modifiers to a RE class, you declare
a <i>RE_Options</i> object, set the appropriate options, and pass this
object to a RE constructor. Example:
<pre>
   RE_options opt;
   opt.set_caseless(true);
   if (RE("HELLO", opt).PartialMatch("hello world")) ...
</pre>
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
<i>option_flags</i> is to facilitate transfer of legacy code from C programs.
This lets you do
<pre>
   RE(pattern,
     RE_Options(PCRE_CASELESS|PCRE_MULTILINE)).PartialMatch(str);
</pre>
However, new code is better off doing
<pre>
   RE(pattern,
     RE_Options().set_caseless(true).set_multiline(true))
       .PartialMatch(str);
</pre>
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: <b>CASELESS()</b>, <b>UTF8()</b>,
<b>MULTILINE()</b>, <b>DOTALL</b>(), and <b>EXTENDED()</b>.
</P>
<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 <b>set_xxxxx()</b> 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:
<pre>
   RE(" ^ xyz \\s+ .* blah$",
     RE_Options()
       .set_caseless(true)
       .set_extended(true)
       .set_multiline(true)).PartialMatch(sometext);

</PRE>
</P>
<br><a name="SEC7" href="#TOC1">SCANNING TEXT INCREMENTALLY</a><br>
<P>
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.
<pre>
  Example: read lines of the form "var = value" from a string.
     string contents = ...;                 // Fill string somehow
     pcrecpp::StringPiece input(contents);  // Wrap in a StringPiece
</PRE>
</P>
<P>
<pre>
     string var;
     int value;
     pcrecpp::RE re("(\\w+) = (\\d+)\n");
     while (re.Consume(&input, &var, &value)) {
       ...;
     }
</pre>
Each successful call to "Consume" will set "var/value", and also
advance "input" so it points past the matched text.
</P>
<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
<pre>
  pcrecpp::RE("(\\w+)").FindAndConsume(&input, &word)
</PRE>
</P>
<br><a name="SEC8" href="#TOC1">PARSING HEX/OCTAL/C-RADIX NUMBERS</a><br>
<P>
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.
<pre>
  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));
</pre>
will leave 64 in a, b, c, and d.
</P>
<br><a name="SEC9" href="#TOC1">REPLACING PARTS OF STRINGS</a><br>
<P>
You can replace the first match of "pattern" in "str" with "rewrite".
Within "rewrite", backslash-escaped digits (\1 to \9) can be
used to insert text matching corresponding parenthesized group
from the pattern. \0 in "rewrite" refers to the entire matching
text. For example:
<pre>
  string s = "yabba dabba doo";
  pcrecpp::RE("b+").Replace("d", &s);
</pre>
will leave "s" containing "yada dabba doo". The result is true if the pattern
matches and a replacement occurs, false otherwise.
</P>
<P>
<b>GlobalReplace</b> is like <b>Replace</b> except that it replaces all
occurrences of the pattern in the string with the rewrite. Replacements are
not subject to re-matching. For example:
<pre>
  string s = "yabba dabba doo";
  pcrecpp::RE("b+").GlobalReplace("d", &s);
</pre>
will leave "s" containing "yada dada doo". It returns the number of
replacements made.
</P>
<P>
<b>Extract</b> is like <b>Replace</b>, 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.
</P>
<br><a name="SEC10" href="#TOC1">AUTHOR</a><br>
<P>
The C++ wrapper was contributed by Google Inc.
<br>
Copyright &copy; 2005 Google Inc.
<p>
Return to the <a href="index.html">PCRE index page</a>.
</p>
1	<html>
2	<head>
3	<title>pcrecpp specification</title>
4	</head>
5	<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6	<h1>pcrecpp man page</h1>
7	<p>
8	Return to the <a href="index.html">PCRE index page</a>.
9	</p>
10	<p>
11	This page is part of the PCRE HTML documentation. It was generated automatically
12	from the original man page. If there is any nonsense in it, please consult the
13	man page, in case the conversion went wrong.
14	<br>
15	<ul>
16	<li><a name="TOC1" href="#SEC1">SYNOPSIS OF C++ WRAPPER</a>
17	<li><a name="TOC2" href="#SEC2">DESCRIPTION</a>
18	<li><a name="TOC3" href="#SEC3">MATCHING INTERFACE</a>
19	<li><a name="TOC4" href="#SEC4">PARTIAL MATCHES</a>
20	<li><a name="TOC5" href="#SEC5">UTF-8 AND THE MATCHING INTERFACE</a>
21	<li><a name="TOC6" href="#SEC6">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a>
22	<li><a name="TOC7" href="#SEC7">SCANNING TEXT INCREMENTALLY</a>
23	<li><a name="TOC8" href="#SEC8">PARSING HEX/OCTAL/C-RADIX NUMBERS</a>
24	<li><a name="TOC9" href="#SEC9">REPLACING PARTS OF STRINGS</a>
25	<li><a name="TOC10" href="#SEC10">AUTHOR</a>
26	</ul>
27	<br><a name="SEC1" href="#TOC1">SYNOPSIS OF C++ WRAPPER</a><br>
28	<P>
29	<b>#include <pcrecpp.h></b>
30	</P>
31	<P>
32	</P>
33	<br><a name="SEC2" href="#TOC1">DESCRIPTION</a><br>
34	<P>
35	The C++ wrapper for PCRE was provided by Google Inc. Some additional
36	functionality was added by Giuseppe Maxia. This brief man page was constructed
37	from the notes in the <i>pcrecpp.h</i> file, which should be consulted for
38	further details.
39	</P>
40	<br><a name="SEC3" href="#TOC1">MATCHING INTERFACE</a><br>
41	<P>
42	The "FullMatch" operation checks that supplied text matches a supplied pattern
43	exactly. If pointer arguments are supplied, it copies matched sub-strings that
44	match sub-patterns into them.
45	<pre>
46	Example: successful match
47	pcrecpp::RE re("h.*o");
48	re.FullMatch("hello");
49
50	Example: unsuccessful match (requires full match):
51	pcrecpp::RE re("e");
52	!re.FullMatch("hello");
53
54	Example: creating a temporary RE object:
55	pcrecpp::RE("h.*o").FullMatch("hello");
56	</pre>
57	You can pass in a "const char*" or a "string" for "text". The examples below
58	tend to use a const char*. You can, as in the different examples above, store
59	the RE object explicitly in a variable or use a temporary RE object. The
60	examples below use one mode or the other arbitrarily. Either could correctly be
61	used for any of these examples.
62	</P>
63	<P>
64	You must supply extra pointer arguments to extract matched subpieces.
65	<pre>
66	Example: extracts "ruby" into "s" and 1234 into "i"
67	int i;
68	string s;
69	pcrecpp::RE re("(\\w+):(\\d+)");
70	re.FullMatch("ruby:1234", &s, &i);
71
72	Example: does not try to extract any extra sub-patterns
73	re.FullMatch("ruby:1234", &s);
74
75	Example: does not try to extract into NULL
76	re.FullMatch("ruby:1234", NULL, &i);
77
78	Example: integer overflow causes failure
79	!re.FullMatch("ruby:1234567891234", NULL, &i);
80
81	Example: fails because there aren't enough sub-patterns:
82	!pcrecpp::RE("\\w+:\\d+").FullMatch("ruby:1234", &s);
83
84	Example: fails because string cannot be stored in integer
85	!pcrecpp::RE("(.*)").FullMatch("ruby", &i);
86	</pre>
87	The provided pointer arguments can be pointers to any scalar numeric
88	type, or one of:
89	<pre>
90	string (matched piece is copied to string)
91	StringPiece (StringPiece is mutated to point to matched piece)
92	T (where "bool T::ParseFrom(const char*, int)" exists)
93	NULL (the corresponding matched sub-pattern is not copied)
94	</pre>
95	The function returns true iff all of the following conditions are satisfied:
96	<pre>
97	a. "text" matches "pattern" exactly;
98
99	b. The number of matched sub-patterns is >= number of supplied
100	pointers;
101
102	c. The "i"th argument has a suitable type for holding the
103	string captured as the "i"th sub-pattern. If you pass in
104	NULL for the "i"th argument, or pass fewer arguments than
105	number of sub-patterns, "i"th captured sub-pattern is
106	ignored.
107	</pre>
108	The matching interface supports at most 16 arguments per call.
109	If you need more, consider using the more general interface
110	<b>pcrecpp::RE::DoMatch</b>. See <b>pcrecpp.h</b> for the signature for
111	<b>DoMatch</b>.
112	</P>
113	<br><a name="SEC4" href="#TOC1">PARTIAL MATCHES</a><br>
114	<P>
115	You can use the "PartialMatch" operation when you want the pattern
116	to match any substring of the text.
117	<pre>
118	Example: simple search for a string:
119	pcrecpp::RE("ell").PartialMatch("hello");
120
121	Example: find first number in a string:
122	int number;
123	pcrecpp::RE re("(\\d+)");
124	re.PartialMatch("x*100 + 20", &number);
125	assert(number == 100);
126	</PRE>
127	</P>
128	<br><a name="SEC5" href="#TOC1">UTF-8 AND THE MATCHING INTERFACE</a><br>
129	<P>
130	By default, pattern and text are plain text, one byte per character. The UTF8
131	flag, passed to the constructor, causes both pattern and string to be treated
132	as UTF-8 text, still a byte stream but potentially multiple bytes per
133	character. In practice, the text is likelier to be UTF-8 than the pattern, but
134	the match returned may depend on the UTF8 flag, so always use it when matching
135	UTF8 text. For example, "." will match one byte normally but with UTF8 set may
136	match up to three bytes of a multi-byte character.
137	<pre>
138	Example:
139	pcrecpp::RE_Options options;
140	options.set_utf8();
141	pcrecpp::RE re(utf8_pattern, options);
142	re.FullMatch(utf8_string);
143
144	Example: using the convenience function UTF8():
145	pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8());
146	re.FullMatch(utf8_string);
147	</pre>
148	NOTE: The UTF8 flag is ignored if pcre was not configured with the
149	<pre>
150	--enable-utf8 flag.
151	</PRE>
152	</P>
153	<br><a name="SEC6" href="#TOC1">PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE</a><br>
154	<P>
155	PCRE defines some modifiers to change the behavior of the regular expression
156	engine. The C++ wrapper defines an auxiliary class, RE_Options, as a vehicle to
157	pass such modifiers to a RE class. Currently, the following modifiers are
158	supported:
159	<pre>
160	modifier description Perl corresponding
161
162	PCRE_CASELESS case insensitive match /i
163	PCRE_MULTILINE multiple lines match /m
164	PCRE_DOTALL dot matches newlines /s
165	PCRE_DOLLAR_ENDONLY $ matches only at end N/A
166	PCRE_EXTRA strict escape parsing N/A
167	PCRE_EXTENDED ignore whitespaces /x
168	PCRE_UTF8 handles UTF8 chars built-in
169	PCRE_UNGREEDY reverses * and *? N/A
170	PCRE_NO_AUTO_CAPTURE disables capturing parens N/A (*)
171	</pre>
172	(*) Both Perl and PCRE allow non capturing parentheses by means of the
173	"?:" modifier within the pattern itself. e.g. (?:ab\|cd) does not
174	capture, while (ab\|cd) does.
175	</P>
176	<P>
177	For a full account on how each modifier works, please check the
178	PCRE API reference page.
179	</P>
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	<pre>
185	bool caseless()
186	</pre>
187	which returns true if the modifier is set, and
188	<pre>
189	RE_Options & set_caseless(bool)
190	</pre>
191	which sets or unsets the modifier. Moreover, PCRE_EXTRA_MATCH_LIMIT can be
192	accessed through the <b>set_match_limit()</b> and <b>match_limit()</b> member
193	functions. Setting <i>match_limit</i> 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 <i>match_limit</i> to zero disables
197	match limiting. Alternatively, you can call <b>match_limit_recursion()</b>
198	which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to limit how much PCRE
199	recurses. <b>match_limit()</b> limits the number of matches PCRE does;
200	<b>match_limit_recursion()</b> limits the depth of internal recursion, and
201	therefore the amount of stack that is used.
202	</P>
203	<P>
204	Normally, to pass one or more modifiers to a RE class, you declare
205	a <i>RE_Options</i> object, set the appropriate options, and pass this
206	object to a RE constructor. Example:
207	<pre>
208	RE_options opt;
209	opt.set_caseless(true);
210	if (RE("HELLO", opt).PartialMatch("hello world")) ...
211	</pre>
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	<i>option_flags</i> is to facilitate transfer of legacy code from C programs.
215	This lets you do
216	<pre>
217	RE(pattern,
218	RE_Options(PCRE_CASELESS\|PCRE_MULTILINE)).PartialMatch(str);
219	</pre>
220	However, new code is better off doing
221	<pre>
222	RE(pattern,
223	RE_Options().set_caseless(true).set_multiline(true))
224	.PartialMatch(str);
225	</pre>
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: <b>CASELESS()</b>, <b>UTF8()</b>,
229	<b>MULTILINE()</b>, <b>DOTALL</b>(), and <b>EXTENDED()</b>.
230	</P>
231	<P>
232	If you need to set several options at once, and you don't want to go through
233	the pains of declaring a RE_Options object and setting several options, there
234	is a parallel method that give you such ability on the fly. You can concatenate
235	several <b>set_xxxxx()</b> member functions, since each of them returns a
236	reference to its class object. For example, to pass PCRE_CASELESS,
237	PCRE_EXTENDED, and PCRE_MULTILINE to a RE with one statement, you may write:
238	<pre>
239	RE(" ^ xyz \\s+ .* blah$",
240	RE_Options()
241	.set_caseless(true)
242	.set_extended(true)
243	.set_multiline(true)).PartialMatch(sometext);
244
245	</PRE>
246	</P>
247	<br><a name="SEC7" href="#TOC1">SCANNING TEXT INCREMENTALLY</a><br>
248	<P>
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	<pre>
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	</PRE>
259	</P>
260	<P>
261	<pre>
262	string var;
263	int value;
264	pcrecpp::RE re("(\\w+) = (\\d+)\n");
265	while (re.Consume(&input, &var, &value)) {
266	...;
267	}
268	</pre>
269	Each successful call to "Consume" will set "var/value", and also
270	advance "input" so it points past the matched text.
271	</P>
272	<P>
273	The "FindAndConsume" operation is similar to "Consume" but does not
274	anchor your match at the beginning of the string. For example, you
275	could extract all words from a string by repeatedly calling
276	<pre>
277	pcrecpp::RE("(\\w+)").FindAndConsume(&input, &word)
278	</PRE>
279	</P>
280	<br><a name="SEC8" href="#TOC1">PARSING HEX/OCTAL/C-RADIX NUMBERS</a><br>
281	<P>
282	By default, if you pass a pointer to a numeric value, the
283	corresponding text is interpreted as a base-10 number. You can
284	instead wrap the pointer with a call to one of the operators Hex(),
285	Octal(), or CRadix() to interpret the text in another base. The
286	CRadix operator interprets C-style "0" (base-8) and "0x" (base-16)
287	prefixes, but defaults to base-10.
288	<pre>
289	Example:
290	int a, b, c, d;
291	pcrecpp::RE re("(.) (.) (.) (.)");
292	re.FullMatch("100 40 0100 0x40",
293	pcrecpp::Octal(&a), pcrecpp::Hex(&b),
294	pcrecpp::CRadix(&c), pcrecpp::CRadix(&d));
295	</pre>
296	will leave 64 in a, b, c, and d.
297	</P>
298	<br><a name="SEC9" href="#TOC1">REPLACING PARTS OF STRINGS</a><br>
299	<P>
300	You can replace the first match of "pattern" in "str" with "rewrite".
301	Within "rewrite", backslash-escaped digits (\1 to \9) can be
302	used to insert text matching corresponding parenthesized group
303	from the pattern. \0 in "rewrite" refers to the entire matching
304	text. For example:
305	<pre>
306	string s = "yabba dabba doo";
307	pcrecpp::RE("b+").Replace("d", &s);
308	</pre>
309	will leave "s" containing "yada dabba doo". The result is true if the pattern
310	matches and a replacement occurs, false otherwise.
311	</P>
312	<P>
313	<b>GlobalReplace</b> is like <b>Replace</b> except that it replaces all
314	occurrences of the pattern in the string with the rewrite. Replacements are
315	not subject to re-matching. For example:
316	<pre>
317	string s = "yabba dabba doo";
318	pcrecpp::RE("b+").GlobalReplace("d", &s);
319	</pre>
320	will leave "s" containing "yada dada doo". It returns the number of
321	replacements made.
322	</P>
323	<P>
324	<b>Extract</b> is like <b>Replace</b>, except that if the pattern matches,
325	"rewrite" is copied into "out" (an additional argument) with substitutions.
326	The non-matching portions of "text" are ignored. Returns true iff a match
327	occurred and the extraction happened successfully; if no match occurs, the
328	string is left unaffected.
329	</P>
330	<br><a name="SEC10" href="#TOC1">AUTHOR</a><br>
331	<P>
332	The C++ wrapper was contributed by Google Inc.
333	<br>
334	Copyright © 2005 Google Inc.
335	<p>
336	Return to the <a href="index.html">PCRE index page</a>.
337	</p>