#!/usr/bin/perl
use strict;
use warnings;
use Benchmark qw(cmpthese);

my %case=(
  a => sub{ return 1*shift; },
  b => sub{ return 2*shift; },
  c => sub{ return 3*shift; },
  d => sub{ return 4*shift; },
);

*my_a=$case{a};
*my_b=$case{b};
*my_c=$case{c};
*my_d=$case{d};

sub rstr{ return chr(int(rand(4))+97) }
sub gto{ goto $case{rstr()}; }
sub rcl{ $case{rstr()}->(@_); }
sub scl{ &{ $case{rstr()} }; }
sub als
{
  my $f=rstr();
  $f eq 'a' and return my_a(@_);
  $f eq 'b' and return my_b(@_);
  $f eq 'c' and return my_c(@_);
  $f eq 'd' and return my_d(@_);
}

cmpthese(1000000, {
  goto    => sub{ gto(55); },
  refcall => sub{ rcl(55); },
  alias   => sub{ als(55); },
  subcall => sub{ scl(55); },
});

            Rate   alias refcall    goto subcall
alias   400000/s      --    -11%    -16%    -20%
refcall 450450/s     13%      --     -5%    -10%
goto    473934/s     18%      5%      --     -6%
subcall 502513/s     26%     12%      6%      --