Joe Yes that's cracked it! I can see you've given values to @A and @B before solving for @C but in Prolog I wasn't aware that the order mattered...There again the calculation is being done in Lisp. As a result of Alex's response this morning I added more parenthesis and that seemed to solve what I was doing last night. I'll have to check you're level of bracketing against mine.
Alex I'm just trying to get Profit from Sales - Cogs and was struggling to produce a minus predicate in pilog i.e. harnessing picolisps '-'. Sorry for not being clear. The problem is...for each item...Sales, Profit etc...I'll rarely have a single value to work with ...just a list... so the formulae do more than just get an end result...they also choose which of the numbers in the various lists "work" together. Thank you both for your examples. That's really helped. Best Regards Dean On 27 November 2016 at 17:59, Alexander Burger <[email protected]> wrote: > Hi Dean > > On Sun, Nov 27, 2016 at 05:42:21PM +0000, dean wrote: > > (prove (goal '( (^ @X (- (-> @A) (-> @B) )) (equal @A 4) (equal @B 2) > ))) > > -> NIL > > > > -> wasn't the "one" in this case > > I'm not sure I understand the problem, but the most natural way for a > diff predicate is perhaps > > : (be - (@A @B @Diff) > (^ @Diff (- (-> @A) (-> @B))) ) > -> - > > : (? @X 7 @Y 3 (- @X @Y @Res)) > @X=7 @Y=3 @Res=4 > > : (? (- 10 3 @X)) > @X=7 > > ♪♫ Alex > -- > UNSUBSCRIBE: mailto:[email protected]?subject=Unsubscribe >
