#!/usr/bin/perl
use warnings;
use strict;

use Benchmark qw{ cmpthese };

sub precat {
    my ($string, $prefix) = @_;
    $string = $prefix . $string;
    $string
}

sub Substr {
    my ($string, $prefix) = @_;
    substr $string, 0, 0, $prefix;
    $string
}

sub subst {
    my ($string, $prefix) = @_;
    $string =~ s/^/$prefix/;
    $string
}

use Test::More;
is precat('def', 'abc'), 'abcdef', 'correct concat';
is Substr('def', 'abc'), 'abcdef', 'same substr';
is subst('def', 'abc'), 'abcdef', 'same subst';
done_testing(3);

cmpthese( -3,
           { precat => q( precat 'def', 'abc' ),
             substr => q( Substr 'def', 'abc' ),
             subst  => q( subst  'def', 'abc' ),
           });