I'm not really sure why you'd want to do this. Things like this make code difficult to maintain. If you came back to the code in say 6 months and added a regular expression you might wonder why it wasn't matching properly. All for saving yourself 1 keystroke per regexp.

Also, case insensitive regexps make the regular expression do more work. That said, you could probably use Filter::Simple to impliment something like this:

Untested, possibly broken, almost certainly stupid code follows:

package rxMatchAnyCase;
use strict;
use Filter::Simple;

FILTER_ONLY( regex => sub { $_ = "(?i:$_)" } );

1;
[download]

Then you'd just "use rxMatchAnyCase" in your script.