Hi pd, > I'm using picolisp version 18.12.27 C in a debian 10.10 based distro, > ... > I'm playing with pilog and there're some examples that does not run: > ... > (^ @I (inc @C)) ) > ... > I can make it work if I use the -> functon this way: > ... > (^ @I (inc (-> @C))) ) > > Is the reference documentation incorrect?
No, but it seems that you looked at the reference for pil21. The syntax for calling Lisp expressions in Pilog was made a little friendlier in pil21, by binding variables directly, so that calling '->' is normally not needed any more. > 2- the example of factorial in Mia's blog [2] : > ... > Again I get it working using the -> function this way: Yes, exactly. So for pil64 and pil32 the old syntax is still required. > I assume the use of -> function is needed but that means picolisp > documentation and Mia's blog is wrong. Not wrong, but it focuses exclusively on pil21. > ... > but I cannot get an answer for the inverse query: > > : (? (factorial @X 120)) > -> NIL This is another issue. This Pilog version of factorial cannot do reverse lookup, as it calculate numeric values via Lisp calls. > Also I would like to know if pilog unification deals with compound > predicates, I mean, in prolog you can write: > > p(a). > p(R(y)). > ? p( X ) > X=a > X=R(y) > > Querying for values of X veryfing a p predicate. How can you get that in > pilog? Yes, you can do that, but not in that direct syntax. You could take a look at how 'not', 'call' or 'or' are implemented in @lib/pilog.l for examples. ☺/ A!ex -- UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe
