I suspect that adding my cmt so late will not add to its visibility however a solution that I find to be semantically appealing is along the lines of:

#!/usr/bin/perl -l

use strict;
use warnings;

sub is {
    bless \shift, '_ghgh';
}

sub _ghgh::in {
    my $x=${ shift, };
    $x eq $_ and return 1 for @_;
    0;
}

print is($_)->in(qw/foo bar baz/) ? 'yes' : 'no'
  for qw/bar fred/;

__END__
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