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Re: Identifying if a variable is the product of a qr//

by JayBonci (Curate)
on Apr 25, 2002 at 10:59 UTC ( #161915=note: print w/replies, xml ) Need Help??

in reply to Identifying if a variable is the product of a qr//

So I'll take a stab at this, and maybe I'm missing what you're asking.

If you bless in a regular expression, it becomes a SCALAR, and as far as I can tell, there's no way to come up with the direct reference of it again, without putting it into regular expression context, like you have (but the only way I can see to do that is to actually use it). Then perl's internal magic kicks in, and blammo, it works.

However, this code below, works to determine whether a blessed thingy is a regexp:
#!/usr/bin/perl -w use strict; use warnings; use Data::Dumper; my $rex = qr/[A-Z]o[A-Z]/; my $bar = \$rex; #my $blessed = bless qr/[A-Z]o[A-Z]/,'foo'; my $blessed = bless $bar, 'foo'; $\="\n"; $,=":\t"; print "Rex ",ref $rex; print "Bless",ref $blessed; print "Rex ",$rex,"WoW"=~$rex ? "WoW" : "---"; print "Bless",$blessed,"WoW"=~$$blessed ? "WoW" : "---"; print "Rex ",$rex,"wow"=~$rex ? "!WoW" : "---"; print "Bless",$blessed,"wow"=~$$blessed ? "!WoW" : "---"; print "Rex ",Dumper($rex); print "Bless",Dumper($blessed); print "Blessed bar", ref $$blessed;
lends me back:
Rex : Regexp Bless: foo Rex : (?-xism:[A-Z]o[A-Z]): WoW Bless: foo=SCALAR(0x80fd428): WoW Rex : (?-xism:[A-Z]o[A-Z]): --- Bless: foo=SCALAR(0x80fd428): --- Rex : $VAR1 = qr/(?-xism:[A-Z]o[A-Z])/; Bless: $VAR1 = bless( do{\(my $o = qr/(?-xism:[A-Z]o[A-Z])/)}, 'foo' +); Blessed bar: Regexp

So you can work around it, by blessing references to references in, thus making the internal reference type of 'ref' and then maybe you don't have that layer of blessed magic-ness to work around. Is it because there is no way to put a scalar in regexp context without actually running it?


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