Add a whilst keyword to Perl

whilst.pl

#!/usr/bin/perl
#
# Inspired by https://github.com/mattt/BritishInvasion
#
# This is still a terrible idea. Just dreadful.

use 5.016;
use warnings;

BEGIN {
    package BritishInvasion;

    use Keyword::Simple;

    sub import {
        Keyword::Simple::define( 'whilst', sub {
                my $ref = shift;
                substr( $$ref, 0, 0 ) = 'while';
            } );
    }

    sub unimport {
        Keyword::Simple::undefine('whilst');
    }
}

BEGIN {
    BritishInvasion->import;
}

my $i = 0;
whilst ( $i < 10 ) {
    say $i++;
}