Replaces Perl's regex engine in a given *lexical scope*

So put the use within curly blocks.

Thank you for your answers. OK, so this was very simple once I tried it out on a very small piece of code instead of what I was working on. I did not realize that you could just stick {} pretty much anywhere you want. Example below, in case anyone is interested.

#!/usr/bin/perl
use strict;
use warnings;

use re::engine::TRE max_cost => 5;

my $seq1 = "TTTTACGAGAGAATATGTTAGGTGAAGGAACCTCTATCTGAGAGAAAAA";
my $seq2 = "TTTTGAGCTCGTTGTCGATCCGAGGTACTTTTGAATCCGCAGTTTCTTG";

if ("A pearl is a hard object produced ..." =~ /\(Perl\)/i)
    {
     print "$1\n";
    }


if (($seq2 =~ /GTTGTTCGATCCAGGTAC/) && ($seq1 =~ /ACGAGAGATAGATGA/))
    {
     print "Have a match\n";
    }
[download]

This will print 'pearl' and "Have a match".

#!/usr/bin/perl
use strict;
use warnings;

my $seq1 = "TTTTACGAGAGAATATGTTAGGTGAAGGAACCTCTATCTGAGAGAAAAA";
my $seq2 = "TTTTGAGCTCGTTGTCGATCCGAGGTACTTTTGAATCCGCAGTTTCTTG";

if ("A pearl is a hard object produced ..." =~ /\(Perl\)/i)
   {
    print "$1\n";
   }

 {
  use re::engine::TRE max_cost => 5;

  if (($seq2 =~ /GTTGTTCGATCCAGGTAC/) && ($seq1 =~ /ACGAGAGATAGATGA/))
      {
        print "Have a match\n";
      }
  }
[download]

This will only print out "Have a match".

"I did not realize that you could just stick {} pretty much anywhere you want."

That's called a "block", and they can't quite go anywhere, but pretty close.

Blocks are how we limit the "scope" of something. Anything defined within that block is limited to that scope. This is where my and local for example come in to play. Here's a couple of examples:

use warnings;
use strict;

my $thing = 123;

{
    my $thing = 456;
}

print $thing; # 123

open my $fh, '<', 'file.txt' or die $!;

{
    local $/; # slurp in a file
    my $contents = <$fh>
    ...
}

# now we go back to reading a file line-by-line again

while (<$fh>){
   ...
}
[download]

Subroutines (functions/methods) are blocks as well, and some functions even take blocks as parameters (or operate in "block mode" so it appears to take a block as a param):

my @list = map {$_ => 1} @other_list;
my @filtered_list = grep {$_ =~ /blah/} @some_list;
[download]

...etc.

Please see AnomalousMonk's post here for how my above example is actually quite broken if taken literally. Haste took rank, but we have people who correct hasty things thankfully. I should have added an "untested" warning or better.

There is nothing wrong with cross-posting questions, but it is considered polite to inform the reader and provide links, to avoid duplication of work in various parts of the Internet.