I've got a very large and complex distribution where several of the modules use a pretty high number of somewhat complex regexes. I have decided instead of having them peppered throughout the code, I'd create a new module, Regex.pm that would house and return these regexes based on name.

Now, this all works well and fine after some fiddling and learning where certain flags need to be set. Here is a basic example:

use warnings;
use strict;

package Re; {
    my %h = (
        re => qr/
            [Pp]erl-\d\.\d+\.\d+(?:_\w+)?
            \s+===.*?
            (?=(?:[Pp]erl-\d\.\d+\.\d+(?:_\w+)?\s+===|$))
        /xs,
    );
    sub re {
        return $h{re};
    }
}

package main; {

    my $str;

    {
        local $/;
        $str = <DATA>;
    }

    my $re = Re::re();
    my @results = $str =~ /$re/g;

    print scalar @results;
}

__DATA__
perl-5.26.1
==========
Reading '/home/spek/.cpan/Metadata'
  Database was generated on Tue, 13 Feb 2018 15:29:02 GMT
App::cpanminus is up to date (1.7043).
--> Working on .
Configuring /home/spek/repos/mock-sub ... OK
<== Installed dependencies for .. Finishing.
--> Working on .
Configuring /home/spek/repos/mock-sub ... Generating a Unix-style Make
+file
Writing Makefile for Mock::Sub
Writing MYMETA.yml and MYMETA.json
OK
Building and testing Mock-Sub-1.10 ... Skip blib/lib/Mock/Sub.pm (unch
+anged)
Skip blib/lib/Mock/Sub/Child.pm (unchanged)
Manifying 2 pod documents
PERL_DL_NONLAZY=1 "/home/spek/perl5/perlbrew/perls/perl-5.26.1/bin/per
+l" "-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef *Test::Har
+ness::Switches; test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
t/00-load.t .................... ok
t/01-called.t .................. ok
t/02-called_count.t ............ ok
t/03-instantiate.t ............. ok
t/04-return_value.t ............ ok
t/05-side_effect.t ............. ok
t/06-reset.t ................... ok
t/07-name.t .................... ok
t/08-called_with.t ............. ok
t/09-void_context.t ............ ok
t/10-unmock.t .................. ok
t/11-state.t ................... ok
t/12-mocked_subs.t ............. ok
t/13-mocked_objects.t .......... ok
t/14-core_subs.t ............... ok
t/15-remock.t .................. ok
t/16-non_exist_warn.t .......... ok
t/17-no_warnings.t ............. ok
t/18-bug_25-retval_override.t .. ok
t/19-return_params.t ........... ok
t/manifest.t ................... skipped: Author tests not required fo
+r installation
t/pod-coverage.t ............... skipped: Author tests not required fo
+r installation
t/pod.t ........................ skipped: Author tests not required fo
+r installation
All tests successful.
Files=23, Tests=243,  2 wallclock secs ( 0.13 usr  0.04 sys +  1.75 cu
+sr  0.13 csys =  2.05 CPU)
Result: PASS
OK
Successfully tested Mock-Sub-1.10

[download]

In the code, I've got this:

    my $re = Re::re();
    my @results = $str =~ /$re/g;

[download]

What I'm wondering, and haven't been able to sort out if it's possible, is skip the variable instantiation, and use the function call directly when using the regex, like this:

    my @results = $str =~ /Re::re()/g;

[download]

Doable, or am I chasing down something impossible?

In reply to Use function as a regex by stevieb

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