Hi Perl Monks. Got another one to lay on you: In the 'Intermediate Perl' book, it is discussing the Regexp::Assemble module.

After the brief discussion of how it optimizes the expression it says 'If you are using v5.10 or later, Perl already does this for you.'

I did a quick (not exactly comprehensive) script to check what that statement was on about

use 5.020;
use Regexp::Assemble;

my $re = Regexp::Assemble->new;
for('blah', 'bleh', 'chicken', 'woofie', 'snake', 'snakes', 'woofies',
+ 'chicken-woofy'){
    $re->add("\Q$_");
}

say $re->re;

my $newre = qr/blah|bleh|chicken|woofie|snake|snakes|woofies|chicken-w
+oofy/;
say $newre;

[download]

The result:

(?^:(?:chicken(?:-woofy)?|woofies?|bl[ae]h|snakes?))
(?^u:(blah)|(bleh)|(chicken)|(woofie)|(snake)|(snakes)|(woofies)|(chic
+ken-woofy))

[download]

What's the deal? Does it just happen internally when /matching|substituting/? Or do I have the wrong idea completely?

Thanks for your time in reading this

In reply to Optimization of Regexes by shadowSage

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