use strict;
my $str = '{foreach $groups as $name => $val} FFFFFFFFFFFFF {/foreach}';
my $regex = qr/{[ \t]*foreach[ \t]*\$(_*[A-Za-z]+[A-Za-z0-9_]*)[ \t]*as[ \t]*\$(_*[A-Za-z]+[A-Za-z0-9_]*)(?:[ \t]=>[ \t]*\$(_*[A-Za-z]+[A-Za-z0-9_]*))?[ \t]*}(.*){[ \t]*\/foreach[ \t]*}/isp;
if ( $str =~ /$regex/ ) {
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