use strict;
my $str = '@FIELDLIST=field_1,field_2
@STRING="Bar"
@JSON={"foo":"bar"}
@CUSTOM-AT-2={"strict":true, "targets":["field_3", "field_7"], "title":"Custom Title", "message":"This is a custom message"}
@CUSTOM-AT-1={"strict":true, "targets":["field_3", "field_7"], "title":"Custom Title", "message":"This is a custom message"}';
my $regex = qr/(?(DEFINE)
(?<tagnames> @CUSTOM-AT-1 | @CUSTOM-AT-2)
(?<number> -? (?= [1-9]|0(?!\d) ) \d+ (\.\d+)? ([eE] [+-]? \d+)? )
(?<boolean> true | false | null )
(?<string> \" ([^\"\\\\]* | \\\\ [\"\\\\bfnrt\/] | \\\\ u [0-9a-f]{4} )* \" )
(?<array> \[ (?: (?&json) (?: , (?&json) )* )? \s* \] )
(?<pair> \s* (?&string) \s* : (?&json) )
(?<object> \{ (?: (?&pair) (?: , (?&pair) )* )? \s* \} )
(?<fieldname> [a-zA-Z0-9\_\-]+ )
(?<json> \s* (?: (?&number) | (?&boolean) | (?&string) | (?&array) | (?&object) ) )
(?<fieldlist> (?: (?&fieldname) (?: , (?&fieldname) )+ )+ ) )
(?<actiontag> (?&tagnames)
)
(?:\=
(?'params'
(?:
(?'match_list'(?&fieldlist))
|
(?'match_json'(?&json))
|
(?'match_string'(?:[[:alnum:]\_\-]+))
)
)
)/mixp;
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