use strict;
use warnings;
use Benchmark  qw/cmpthese/;
my @translation = qw / Zero One Two Three/;
my %trans = (1 => "One", 2 => "Two", 3 => "Three");
my @dispatch = ( sub {return "Zero"}, sub {return "One"}, sub {return "Two"}, sub {return "Three"} );

sub test1 {
    my $var2 = shift;
    return ("One")    if ($var2 =~ /^1/ );
    return ("Two")    if ($var2 =~ /^2/ );
    return ("Three")  if ($var2 =~ /^3/ );
    return undef;
}
sub test2 {
    my $var2 = substr shift, 0, 1;
    return ("One")    if ($var2 == 1 );
    return ("Two")    if ($var2 == 2 );
    return ("Three")  if ($var2 == 3 );
    return undef;
}
sub test3 {
    return $translation[(substr shift, 0, 1)];
}
sub test4 {
	my $var = shift;
	return $trans{$1} if $var =~ /^(\d)\./ ;
}
sub test5 {
	my $var = substr shift, 0, 1;
	eval { goto "_$var" }    or
        return "Other"; 
    _1: return "One"  ;
    _2: return "Two"  ; 
    _3: return "Three"; 
}
sub test6 {
	return $dispatch[(substr shift, 0, 1)]->();
}
	
cmpthese( -1,
	{
	_linear_1      => q {test1("2.01.000")},
	_linear_2      => q {test2("2.01.000")},
	_array         => q {test3("2.01.000")},
	_hash_regex    => q {test4("2.01.000")},
	_goto          => q {test5("2.01.000")},
	_dispatch      => q {test6("2.01.000")},
	}
)

##</code><code>##

$ perl test_if.pl
                 Rate _hash_regex     _goto linear_1 linear_2 _dispatch   _array
_hash_regex  831494/s          --      -29%     -46%     -52%      -54%     -70%
_goto       1173439/s         41%        --     -24%     -32%      -36%     -57%
_linear_1    1538868/s         85%       31%       --     -10%      -16%     -44%
_linear_2    1714704/s        106%       46%      11%       --       -6%     -37%
_dispatch   1827212/s        120%       56%      19%       7%        --     -33%
_array      2735932/s        229%      133%      78%      60%       50%       --