/[pcre]/code/trunk/doc/pcrepattern.3
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revision 341 by ph10, Sat Apr 19 16:41:04 2008 UTC revision 345 by ph10, Mon Apr 28 15:10:02 2008 UTC
# Line 318  parenthesized subpatterns. Line 318  parenthesized subpatterns.
318  .SS "Absolute and relative subroutine calls"  .SS "Absolute and relative subroutine calls"
319  .rs  .rs
320  .sp  .sp
321  For compatibility with Oniguruma, the non-Perl syntax \eg followed by a name or  For compatibility with Oniguruma, the non-Perl syntax \eg followed by a name or
322  a number enclosed either in angle brackets or single quotes, is an alternative  a number enclosed either in angle brackets or single quotes, is an alternative
323  syntax for referencing a subpattern as a "subroutine". Details are discussed  syntax for referencing a subpattern as a "subroutine". Details are discussed
324  .\" HTML <a href="#onigurumasubroutines">  .\" HTML <a href="#onigurumasubroutines">
325  .\" </a>  .\" </a>
326  later.  later.
327  .\"  .\"
328  Note that \eg{...} (Perl syntax) and \eg<...> (Oniguruma syntax) are \fInot\fP  Note that \eg{...} (Perl syntax) and \eg<...> (Oniguruma syntax) are \fInot\fP
329  synonymous. The former is a back reference; the latter is a subroutine call.  synonymous. The former is a back reference; the latter is a subroutine call.
330  .  .
331  .  .
# Line 1259  support is available, \eX{3} matches thr Line 1259  support is available, \eX{3} matches thr
1259  which may be several bytes long (and they may be of different lengths).  which may be several bytes long (and they may be of different lengths).
1260  .P  .P
1261  The quantifier {0} is permitted, causing the expression to behave as if the  The quantifier {0} is permitted, causing the expression to behave as if the
1262  previous item and the quantifier were not present. This may be useful for  previous item and the quantifier were not present. This may be useful for
1263  subpatterns that are referenced as  subpatterns that are referenced as
1264  .\" HTML <a href="#subpatternsassubroutines">  .\" HTML <a href="#subpatternsassubroutines">
1265  .\" </a>  .\" </a>
1266  subroutines  subroutines
1267  .\"  .\"
1268  from elsewhere in the pattern. Items other than subpatterns that have a {0}  from elsewhere in the pattern. Items other than subpatterns that have a {0}
1269  quantifier are omitted from the compiled pattern.  quantifier are omitted from the compiled pattern.
1270  .P  .P
1271  For convenience, the three most common quantifiers have single-character  For convenience, the three most common quantifiers have single-character
# Line 2053  processing option does not affect the ca Line 2053  processing option does not affect the ca
2053  .SH "ONIGURUMA SUBROUTINE SYNTAX"  .SH "ONIGURUMA SUBROUTINE SYNTAX"
2054  .rs  .rs
2055  .sp  .sp
2056  For compatibility with Oniguruma, the non-Perl syntax \eg followed by a name or  For compatibility with Oniguruma, the non-Perl syntax \eg followed by a name or
2057  a number enclosed either in angle brackets or single quotes, is an alternative  a number enclosed either in angle brackets or single quotes, is an alternative
2058  syntax for referencing a subpattern as a subroutine, possibly recursively. Here  syntax for referencing a subpattern as a subroutine, possibly recursively. Here
2059  are two of the examples used above, rewritten using this syntax:  are two of the examples used above, rewritten using this syntax:
2060  .sp  .sp
2061    (?<pn> \e( ( (?>[^()]+) | \eg<pn> )* \e) )    (?<pn> \e( ( (?>[^()]+) | \eg<pn> )* \e) )
2062    (sens|respons)e and \eg'1'ibility    (sens|respons)e and \eg'1'ibility
2063  .sp  .sp
2064  PCRE supports an extension to Oniguruma: if a number is preceded by a  PCRE supports an extension to Oniguruma: if a number is preceded by a
2065  plus or a minus sign it is taken as a relative reference. For example:  plus or a minus sign it is taken as a relative reference. For example:
2066  .sp  .sp
2067    (abc)(?i:\eg<-1>)    (abc)(?i:\eg<-1>)
2068  .sp  .sp
2069  Note that \eg{...} (Perl syntax) and \eg<...> (Oniguruma syntax) are \fInot\fP  Note that \eg{...} (Perl syntax) and \eg<...> (Oniguruma syntax) are \fInot\fP
2070  synonymous. The former is a back reference; the latter is a subroutine call.  synonymous. The former is a back reference; the latter is a subroutine call.
2071  .  .
2072  .  .
# Line 2117  remarks apply to the PCRE features descr Line 2117  remarks apply to the PCRE features descr
2117  .P  .P
2118  Since these verbs are specifically related to backtracking, most of them can be  Since these verbs are specifically related to backtracking, most of them can be
2119  used only when the pattern is to be matched using \fBpcre_exec()\fP, which uses  used only when the pattern is to be matched using \fBpcre_exec()\fP, which uses
2120  a backtracking algorithm. With the exception of (*FAIL), which behaves like a  a backtracking algorithm. With the exception of (*FAIL), which behaves like a
2121  failing negative assertion, they cause an error if encountered by  failing negative assertion, they cause an error if encountered by
2122  \fBpcre_dfa_exec()\fP.  \fBpcre_dfa_exec()\fP.
2123  .P  .P
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