user=> (defmulti length empty?) #'user/length user=> (defmethod length true [x] 0) #<MultiFn clojure.lang.mult...@1807ca8>
user=> (defmethod length false [x] (+ 1 (length (rest x)))) #<MultiFn clojure.lang.mult...@1807ca8> user=> (length [1 2 3 4]) 4 On Fri, Aug 21, 2009 at 12:41 PM, Michel Salim<michael.silva...@gmail.com> wrote: > > On Fri, 2009-08-21 at 11:02 -0700, Sigrid wrote: >> Hi, >> >> I read the related story on InfoQ and found it an extremely >> interesting and motivating read, Clojure being applied in such an >> interesting field as machine learning! >> >> There is something in the article I'd like to understand better, so >> i'm just asking here on the group: >> >> "The way that Rich elected to de-couple destructuring bind from >> pattern matching was brilliant." >> >> Could someone point me to what the difference is? I know pattern >> matching e.g. from the PLT scheme implementation, and there the >> pattern matching also provides the binding and destructuring I >> think...? >> > Clojure allows destructuring of vectors, which happens to be what its > functions' argument lists are, so you get most of the benefits of > pattern matching. It's not full-blown, though, so (correct me if I'm > wrong) the equivalent of this is not possible: > > length [] = 0 > length (_:xs) = 1 + (length xs) > > Regards, > > -- > Michel > > > > > -- And what is good, Phaedrus, And what is not good— Need we ask anyone to tell us these things? --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
