Re: [Datadraw-user] New DataDraw computer language - Grail

[Richard P. <rdp...@gm...>]

Bill, everybody,

Richard again.

I notice a mistake in my closure example.  What if the mutate variable
(called closure_var in my example) gets used by two subroutines?  the first
one who get destroyed will `cascade' delete the var and the other wont be
able to use it anymore.

Well after `cascade' and `mandatory', I guess it is time for a new
decorator.  I would call it `parasitism' for now. (I was tempted by
`garbage_collected' but that would be overwhelming.)  `Parasitism' mean here
that child can live as long as it gets one of its host Parent alive.

Regarding module parameters and relationship decorators, we have up to now:

   - relationship directionality: mutual, parent_only, child_only
   - relationship termination behavior: separation, mandatory, cascade, and
   now parasitism
   - data structure keying information: hash key, comparison function...
   - be my guess: invent your own

`parent_only' and `child_only' are destructive and intimately related to the
internal data structure of the relationship.

Relationship termination behavior is another story.  they are constructive
and independent of the internal data structure.  Therefore they could
probably be defined separately.

decorator relationship.cascade(Parent parent, Child child)
    on Parent.destroy()                      # `on' event driven engine...
becomes inline
        safe foreach parent.clabel(child)    # where do I get this label??
            delete child


Regards

Richard,  a big worm of the can you opened...  ;-)