switch.pl

use strict;
use warnings;
use 5.010;
use Benchmark qw/timethese cmpthese/;

sub action_a {
    my ($a, $b) = @_;
    $b ||= 0;
    return $a + $b;
}
sub action_b {
    my ($a, $b) = @_;
    $b ||= 0;
    return $a - $b;
}
sub action_c {
    my ($a, $b) = @_;
    $b ||= 0;
    return $a * $b;
}
sub action_d {
    my ($a, $b) = @_;
    $b ||= 1;
    return $a / $b;
}

sub param {
    #return 3, 10, 2;
    return (
        int(rand(5)),
        rand(100000),
        rand(100) + 1
    );
}

sub putturn_if {
    my ($act, $a, $b) = @_;
    if ($act == 1) {
        action_a($a, $b);
    } elsif ($act == 2) {
        action_b($a, $b);
    } elsif ($act == 3) {
        action_c($a, $b);
    } elsif ($act == 4) {
        action_d($a, $b);
    } else {
        return 0;
    }
}

sub putturn_given {
    my ($act, $a, $b) = @_;
    given ($act) {
        when (1) { return action_a($a, $b) }
        when (2) { return action_b($a, $b) }
        when (3) { return action_c($a, $b) }
        when (4) { return action_d($a, $b) }
        default { return 0 }
    }
}

my $acts = {
    1 => *action_a,
    2 => *action_b,
    3 => *action_c,
    4 => *action_d,
};

sub putturn_hash {
    my ($act, $a, $b) = @_;
    if ($acts->{$act}) {
        $acts->{$act}->($a, $b);
    } else {
        return 0;
    }
}

my $result = timethese(1000000, {
    if => sub {
        putturn_if(param());
    },
    given => sub {
        putturn_given(param());
    },
    hash => sub {
        putturn_hash(param());
    },
});

cmpthese $result;

__END__
Benchmark: timing 1000000 iterations of given, hash, if...
     given:  5 wallclock secs ( 4.37 usr +  0.01 sys =  4.38 CPU) @ 228310.50/s (n=1000000)
      hash:  3 wallclock secs ( 3.35 usr +  0.01 sys =  3.36 CPU) @ 297619.05/s (n=1000000)
        if:  4 wallclock secs ( 3.34 usr +  0.00 sys =  3.34 CPU) @ 299401.20/s (n=1000000)
          Rate given  hash    if
given 228311/s    --  -23%  -24%
hash  297619/s   30%    --   -1%
if    299401/s   31%    1%    --