Re: [PRD] Proposal for object representation (and ACTION-592 complete)


Michael Kifer wrote:
> these things are called path expressions and they are not necessarily
> single-valued. For instance, FLORA-2 uses them alongside the frames,
> and they are simply shortcuts for some forms of conjunctions of frames.

I have taken the action to rework my proposal to separate the issues of single-valued attributes, and path location.

But that supposes that I understand how path locations can be multi-valued: as much as I understand that, as atomic assertions, frames that associate different values to the same object-attribute pair can be true at the same time; as much I cannot understand how a path expression, as a basic term, can represent more than one value. Actually, dealing with single-valued attributes in a way that seemed intrinsically appropriate for them - which frames are not - and that is quite usual in object-oriented languages was the main reason for my proposal.

I mean, other basic terms, such as a constant symbol, a variable, or a ground function call, represent, cannot represent but a single value: how can a path expression, as a basic term, represent more than one? Of course, it can be set-valued, but it still has a single value, which is the set.

Can you please clarify? An example would, also, certainly help me understand better what you mean.



Received on Monday, 9 March 2009 20:00:33 UTC