use strict;
my $str = 'hsl(10, 50deg, 150%)
HSLA(50.35, .531, 10%)
HSLA(50.5deg, .531%, .9%, 1.0)';
my $regex = qr/(?(DEFINE)
(?<decimal>(?(int)([.][0-9]+)?|[.][0-9]+))
(?<percentage>
(100|
(?<int>([0-9]|[1-9][0-9]))? # Have integer be optional (0-100 only)
(?P>decimal) # Have decimal required when an integer is not included
)
(?<symbol>%)
)
(?<hue>
(?<int>36[0]|3[0-5][0-9]|[12][0-9][0-9]|[1-9]?[0-9])? # Have integer be optional
(?P>decimal) # Have decimal required when an integer is not included
(?<symbol>\s*deg\s*)?
)
(?<alpha>
(?(alpha),\s*(
1[.]0|
(?<int>0)? # Have integer be optional
(?P>decimal) # Have decimal required when integer is not incldue
)\s*)
)
(?<hsl>\s*(?P>hue)\s*,\s*(?P>percentage)\s*,\s*(?P>percentage)\s*)
)
hsl(?<alpha>a)?\((?P>hsl)(?P>alpha)\)/xip;
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