contracts.pl

#!/usr/bin/perl

use strict;
use warnings;

use lib './';
use Contract;
use Contract::Predicate;

sub foo {
    my ($x, $y) = @_;
    my $z = $x + $y;
    return "$x + $y == $z";
}

contract "foo", two_of integer, integer;

my $x = foo 3, 4;