#!/usr/bin/perl

use Benchmark qw( cmpthese );

my( $count, $len )= @ARGV;
$count ||= 10;
$len ||= 5000;
my $string= join '+', map {
    join '', map {('a'..'z')[rand(26)]} 0..rand($len)
} 1..$count;

sub subst {
    $string =~ s/\+/-/g;
    $string =~ s/\-/+/g;
    0;
}

sub trans {
    $string =~ tr/\+/-/;
    $string =~ tr/\-/+/;
    0;
}

cmpthese( -3, {
    a_s => \&subst,
    b_s => \&subst,
    a_t => \&trans,
    b_t => \&trans,
} );

##</code><code>##

       Rate  b_t  a_t  b_s  a_s
b_t  8190/s   --  -1% -40% -40%
a_t  8258/s   1%   -- -39% -40%
b_s 13615/s  66%  65%   --  -1%
a_s 13720/s  68%  66%   1%   --