> My Python code is much more declarative than the given > cKanren code in that regard. Just compare: > http://dosync.posterous.com/another-taste-of-ckanren
I don't think you understand what declarative programming is at its core. Declarative programming To borrow from the ever-present wikipedia: "declarative programming is a programming paradigm that expresses the logic of a computation without describing its control flow.[1] Many languages applying this style attempt to minimize or eliminate side effects by describing what the program should accomplish, rather than describing how to go about accomplishing it.[2] This is in contrast with imperative programming, which requires an explicitly provided algorithm." (see: Declarative Programming) This is where the cKanren code succeeds where the Python code fails. The Python code is all algorithm, and no facts. While the cKanren code is a direct implementation of the facts about the problem: one stone must be 1lb all stones should equal 40lb, etc. The cKanren code leaves the interpretation of these facts up to the logic engine, while the Python code sets strict guidelines that the compiler must follow. If, for instance, it was faster for a given computer to count down from instead of counting up, the Python code would run much slower, by defining the algorithm (by using range, and for loops), you're restricting the interpreter to your view of how to solve the problem. The cKanren compiler/interpreter/whatever is free to solve the problem in any way it pleases, as long as the requirements (facts) are met. The original problem states "find 4 numbers that equal 40 but a combination of any of which can be 1 through 40" it says nothing of range sequences, for loops, etc. Timothy -- 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
