That doesn't work for two reasons.

1. Regexp::Optimizer is a no-op if no alternation is used.

2. Even if Regexp::Optimizer normalized regexps, the normalized regexps still wouldn't be equal since the two regexps are not equivalent. 

use Regexp::Optimizer qw( );
my $o = Regexp::Optimizer->new();
print $o->optimize(qr/123*/),  "\n";  # (?-xism:123*)
print $o->optimize(qr/1233*/), "\n";  # (?-xism:1233*)
print $o->optimize(qr/123+/),  "\n";  # (?-xism:123+)

[download]

The OP didn't ask for a method to check if two regexp are equivalent, but for a method to check if a regexp will match at least everything a second regexp matches.

Update: Added code. Changed formatting.

In reply to Re^2: Compare two regex patterns by ikegami
in thread Compare two regex patterns by atemon

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