Re: Ann: delay pack

On Fri, Aug 9, 2013 at 12:20 PM, Alan Baljeu <[email protected]> wrote:

> How does delay know when the argument is ready to be called?
>

The module has a list of acceptable modes for each
predicate<https://github.com/mndrix/delay/blob/master/prolog/delay.pl#L18>.
 For example

    mode(plus(g,g,_)).
    mode(plus(g,_,g)).
    mode(plus(_,g,g)).

where g means ground and _ means var.  As soon as arguments are
instantiated to match one of those modes, the underlying predicate is
called.  Inside the module, those mode/1 facts are expanded into code like:

    delay(plus(C, A, B)) :-
when((ground(A), ground(B);ground(C), ground(B);ground(C), ground(A)),
     plus(C, A, B))

-- 
Michael
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