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Re^2: Is there really no @LAST_MATCH_START equivalent for named capture groups?

by LanX (Canon)
on Jan 30, 2013 at 10:51 UTC ( #1016024=note: print w/ replies, xml ) Need Help??


in reply to Re: Is there really no @LAST_MATCH_START equivalent for named capture groups?
in thread Is there really no @LAST_MATCH_START equivalent for named capture groups?

> Otherwise you could use one of the RegEx parsing modules on the regex to associate name to index.

It's a hack but it gives you a hash mapping each name to it's index:

(see Dynamically inspecting Regex OP-Codes at runtime? for an explanation)

use strict; use warnings; use Data::Dump; my $a=qr/(?<C>1)(?<D>2)(3)(?<A>4)/; my $parsing=parse_regex($a); # parse lines like ' 1: OPEN1 'C' (3)' my %named_captures = ($parsing =~ /^ \s{1,3}\d{1,3}:\s+ # token number OPEN(\d)[ ]'(\w+)' # group(nr) 'name' [ ]\(\d+\) # next token $ /xgm); my %index_named_capture = reverse %named_captures; dd \%index_named_capture; # OUTPUT { A => 4, C => 1, D +=> 2 } sub parse_regex { my $regex=shift; my $re_compilation; # First, save away STDERR open my $SAVEERR, ">&STDERR"; close STDERR; open STDERR, ">", \$re_compilation or die "What the hell?\n"; # Now dynamically recompile a new regex, saving debug_info to $re_co +mpilation eval <<'_code_'; use re 'debug'; my $b=qr/$regex(?:)/; _code_ # Now close and restore STDERR to original condition. close STDERR; open STDERR, ">&", $SAVEERR; return $re_compilation; }
Careful: ATM this can't handle repeated names properly, for this you need to adjust the reverse part.

Cheers Rolf

UPDATES

corrected typo in code


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