#!/usr/local/bin/perl -w
# Doable.pm
# my dbc OOPerl "interface"

use strict;
use warnings;
use FindBin::libs;
use Class::Contract;

package Doable; {
    unless( eval {
        contract {
            # constant
            class attr 'NADA';
            invar { ${self->NADA} = 0; };

            abstract ctor 'new';
            abstract dtor;

            # Control
            abstract method 'doTheThing';

            # Test: DON'T implement doThatThing
            # and hope an exception is raised.
            abstract method 'doThatThing';
                pre { defined ${Doable::caller} };
        }; # end contract

        sub new;
        sub DESTROY;
        sub doTheThing;
        # sub doThatThing;

    1; } # end eval

    ) { die( "\n\nThere has been a breach of contract.\n\n" ); } # end unless

} 1; # end Doable