use warnings;
use strict;

use Benchmark qw{ cmpthese };

# original code by choroba

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
}

# minimal variable declaration

sub precatm {
    $_[1] . $_[0];
}
sub Substrm {
    substr my $string = $_[0], 0, 0, $_[1];
    $string;
}
sub substm {
    ( my $string = $_[0] ) =~ s/^/$_[1]/;
    $string;
}

cmpthese -1, {
    precat  => q( precat  'def', 'abc' ),
    substr  => q( Substr  'def', 'abc' ),
    subst   => q( subst   'def', 'abc' ),

    precatm => q( precatm 'def', 'abc' ),
    substrm => q( Substrm 'def', 'abc' ),
    substm  => q( substm  'def', 'abc' ),
};