I'm currently struggling with the same question. Did you ever happen to reach a satisfying conclusion?
On Saturday, May 25, 2013 at 1:21:08 PM UTC-4, Brian Craft wrote: > > Wondering if anyone can give me some pointers with this, as I dive into > logic programming. Or point me to a more appropriate forum, if this is the > wrong one. I know a lot of you have been trying out core.logic. > > It was all going well until chapter four. The story so far: introduce some > simple function, like cdr, then develop a logic programming equivalent, > repeat. Then in chapter four we get the second commandment, and the > equivalent functions stop being equivalent. Instead, they generate > meaningless results, like 4.18, where the value of z is irrelevant to > whether the equivalent function (mem) would succeed, since the target > pattern appears earlier in the list, but memo outputs an infinite number of > the target pattern. Or they generate incorrect results, like 4.31, where > some of the patterns do not satisfy the equivalent function (rember), like > (a b _.0 d e): z can't be removed unless it unifies with y, in which case > y would have been removed, not z. The chapter concludes by highlighting > this issue with "surprise", a simple example which generates solutions that > don't satisfy the constraints. > > I was hoping, at that point, for insights into accurately translating > functions into their logic programming equivalents, however the chapter > ends with "Please pass the aspirin", and the book continues with more > "second commandment" examples that also produce unhelpful results. > > So, I'm a bit baffled about the point of this exercise. Why is it useful > to have a second commandment that converts functions into logic programming > functions that are superficially similar, but fundamentally different, > producing solutions that are irrelevant or incorrect for the original > function? Is there some different technique that would allow one to > generate correct solutions with logic programming? > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
