+1
On Sat, May 25, 2013 at 8:12 PM, Austin Haas <aus...@pettomato.com> wrote: > > Hi Brian, > > You should post your question to the miniKanren Google group. > > minikan...@googlegroups.com > > -austin > > -- > Austin Haas > Pet Tomato, Inc. > http://pettomato.com > > > On Sat May 25 10:21 , 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/groups/opt_out. > > > > > > -- > -- > 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/groups/opt_out. > > > -- -- 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/groups/opt_out.
