#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };


my $grep = sub {
    my $f = shift;
    return { CODE   => sub { grep $f->($_), @_ },
             Regexp => sub { grep /$f/,     @_ },
             q()    => sub { grep $_ <= $f, @_ },
           }->{ref $f}->(@_);
};

say for qr/[01]/->$grep(1 .. 100);
say '-' x 20;
say for sub { not $_ % 10 }->$grep(1 .. 100);
say '-' x 20;
say for 5->$grep(1 .. 100);