package FunkyNum;
use strict;
use Class::Contract;


contract {
   attr 'val';

   ctor 'new';
     impl { ${self->val} = $_[0] || 0;  }; #arn't I tricky

   method 'plusequal';
     pre   { defined $_[0] };

     impl {
       ${self->val} += $_[0];
     };
   method 'printval';
     impl {
       return ${self->val};
     }
};

##</code><code>##


use strict;
use FunkyNum;
my $x = new FunkyNum 2;
$x->plusequal(2);
print "num is " . $x->printval . "\n";
$x->plusequal(("woah", "there", "fella"));
print "num is " . $x->printval . "\n";
$x->nomethod;

##</code><code>##

pre   { ref $_[0] && $_[0]->isa("FunkyNum") };