rb@cci632.UUCP (Rex Ballard) (07/02/86)
In article <3830@utah-cs.UUCP> u-reddy@utah-cs.UUCP (Uday U-reddy) writes: >In article <270@ubc-cs.UUCP> andrews@ubc-cs.UUCP (Jamie Andrews) writes: >> Well, as far as cut is concerned: it's fairly easy to explain it >>"logically", though not as a predicate or a goal, which is what I assume >>you meant. >>--Jamie. > >Sorry Jamie, I fail to understand this completely. We had lengthy >discussions, in Prolog digest last year, on what is logical and what isn't. >But, to cut (!) the long story short, something is logical if it has a >logical value, like "true", or "false", or even nonstandard logical values >like "neither true nor false" or "both true and false" or whatever. >Further, the logical value of any logical thing should be preserved under >instantiation. > >Now, I am not sure if what you are saying has anything to do with the >logical-ness of these constructs. > >Uday Reddy Now I'm a little confused. Aren't any goals which refer to uninstantiated variables, which are later instantiated, potentially both true and false? I normally think of a cut symbol as an uninstantiated variable that gets instantiated to false. I'm only a novice at this, but it at least helps me to understand it better. Ignorance is bliss :-). Prolog is quickly becoming one of my favorite languages. Rex B.