What I said about keys applies to values and each as well. It's not a backward incompatible change, so no feature needs to be activated. Your code boils down to 

use if $] < 5.012, 'Enumerators';

[download]

Prepending scripts with nine lines of code is not what I was hoping for.

That's because you're trying to write your code inside out. A less messy approach would be to include Enumerators unconditionally, and let it decide if it needs to override each or not. It's not a detail the module's user should worry about. 

# use Enumerators -global;
# use Enumerators qw( each );
# use Enumerators;

package Enumerators;

use Exporter qw( );

our @EXPORT    = qw( each );
our @EXPORT_OK = qw( each );

sub import {
   my $class = shift;
   return if $[ >= 5.012;
   if ($_[0] eq '-global') {
      *CORE::GLOBAL::each = \&each;
   } else {
      goto &Exporter::import;
   }
}

sub each(\[@%]) {
   ...
}

1;

[download]

(Trim out what you don't want.)

Note that this approach works for pragams too. 

package stricter;

sub import {
   require strict;
   strict->import;
   require warnings;
   warnings->import;
}

1;

[download]

use stricter; does the same as use strict; use warnings;

In reply to Re^3: Howto "use" backward compability packages of new "feature"s by ikegami
in thread Howto "use" backward compability packages of new "feature"s by LanX

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