Re: making regex case insensitive

It seems everyone is quite fond of the /i modifier, not to mention their CPU cycles. In colder climates, I find the following helps keep toes warmer, longer:

#!/usr/bin/env perl

use 5.012;
use warnings;
use Carp;

say insensitive('This is a test', qr/this is a test/) ? 'Match!' : 'No
+ match.';

sub insensitive {
    my ($cmp, $re) = @_;
    croak "expecting regexp, got " . ref $re unless 'Regexp' eq ref $r
+e;
    carp "Insensitive use of uninitialized value" unless defined $cmp;

    my ($len, %seen) = length($cmp);
    croak "Not without bignum" if $len > 31;
    while (keys %seen <= 2**$len) {
        return 1 if $cmp =~ $re;
        substr($cmp, int rand $len, 1) ^= ' ';
        undef $seen{$cmp};
    }
    return;
}
[download]

Unicode support is left as an exercise to the reader.

Comment on Re: making regex case insensitive Select or Download Code

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Re^2: making regex case insensitive by hdb (Monsignor) on Jul 17, 2013 at 06:33 UTC
How about doing it more directly? The obvious solution seems to be to compare against `/test\|Test\|tEst\|.../`. The `glob` function will help to create such a pattern: `use strict; use warnings; my $pat = "test"; $pat = join "\|", glob join "", map { "{".uc.",".lc."}"} split //, $pat +; print "$pat\n"; for ( qw( Test test tesT tast ) ) { print "$_\n" if /$pat/; }` [download]	[reply] [d/l] [select]
Re^2: making regex case insensitive by elTriberium (Friar) on Jul 16, 2013 at 18:32 UTC
You really prefer this solution over adding a single "i" to the regex?	[reply]
Re^3: making regex case insensitive by rjt (Curate) on Jul 16, 2013 at 18:59 UTC
You really prefer this solution over adding a single "i" to the regex? You really didn't know my post was a joke?	[reply]
Re^4: making regex case insensitive by marinersk (Priest) on Jul 16, 2013 at 19:21 UTC
Okay, I'll admit, I missed it. I was trying to figure out what the advantage was of doing it your way. I'll go sit in the corner and read Camel or something as pennance.	[reply]
Re^4: making regex case insensitive by elTriberium (Friar) on Jul 16, 2013 at 21:27 UTC
Sorry, missed it ;). I misread the part about keeping toes warm and thought you were seriously suggesting this for faster execution time.	[reply]