use strict;
my $str = 'five blue elephants solve many interesting problems
many large problems ressemble some interesting cars';
my $regex = qr/(?(DEFINE) # start DEFINE block
# pre-define quant subroutine
(?<quant>many|some|five)
# pre-define adj subroutine
(?<adj>blue|large|interesting)
# pre-define object subroutine
(?<object>cars|elephants|problems)
# pre-define noun_phrase subroutine
(?<noun_phrase>(?&quant)\ (?&adj)\ (?&object))
# pre-define verb subroutine
(?<verb>borrow|solve|ressemble)
) # end DEFINE block
##### The regex matching starts here #####
(?&noun_phrase)\ (?&verb)\ (?&noun_phrase)/xp;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html