2017-01-29 21:15 GMT+01:00 Michael Lindon <michael.s.lin...@gmail.com>:
> Not quite what I'm looking for. There is an assigment in the Functional > Programming in Scala coursera course called "funsets" - purely functional > sets. A set is defined by its characteristic functions (a predicate) and > source code can be found here > Looking at it from a functional perspective, it still might be though. Consider: You can treat any set as a predicate, but to treat a predicate as a set, you need to add enumeration (as Christian hinted). https://mwclearning.com/sourcecode/scala/funsets/src/ > main/scala/funsets/FunSets.scala > The enumeration scheme in this scala object is very simplistic: It works for integers between -1000 and 1000. Besides being incomplete, this can easily lead to unnecessarily exponential runtimes: > /** > * The bounds for `forall` and `exists` are +/- 1000. > */ > val bound = 1000 > /** > * Returns whether all bounded integers within `s` satisfy `p`. > */ > def forall(s: Set, p: Int => Boolean): Boolean = { > val filteredSet = filter(s, p) > def iter(a: Int): Boolean = { > if (contains(s, a) && !contains(filteredSet, a)) false > else if (a > bound) true > else iter(a + 1) > } > iter(-bound) > } > /** > * Returns whether there exists a bounded integer within `s` > * that satisfies `p`. > */ > def exists(s: Set, p: Int => Boolean): Boolean = forall(s, union(s,p)) Constraint programming offers a much more sophisticated approach towards enumeration, eagerly skipping whole subsets based on excluded ranges. Maybe that's what the coursera is aiming for ... -- 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.
