use strict;
my $str = '2*2
2+2
2/2
2-2
2^2-2
2^2
2e10^4
2^2^2^2+4
2+2+2+2
2 times 2
2 multiplied by 2
2 multiply 2
2 divide 2
2 divided by 2
2 add 2
2 plus 2
2 minus 2
2 subtract 2
2 to the power of 2 divided by 10
2 multiplied by 10 times 3
2.09187 times 9
-3 times 9
2+-6
2 multiplied by';
my $regex = qr~^((-?\d+(?:\.\d+)?)(?:[*+/^eE-]| (?:to the power of|plus|add|minus|subtract|divided?|times|multipl(?:y|ied))(?: by)?)(?: )?)(?1)*(?2)$~mp;
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