It's a (drastic) performance improvement. The magic number of 3 appears to cover a lot of use cases. Once you get larger than three, it typically is a large number of inputs, i.e. the tail flattens off.
On Mar 23, 5:00 pm, Thomas <thomas.g.kristen...@gmail.com> wrote: > Hi all, > > I've been reading through clojure.core to see examples of fine clojure > style. One thing I've noticed is (what I consider) a weird notation > when parsing parameters for function. As an example, consider the > function juxt: > > (defn juxt > "Alpha - name subject to change. > Takes a set of functions and returns a fn that is the juxtaposition > of those fns. The returned fn takes a variable number of args, and > returns a vector containing the result of applying each fn to the > args (left-to-right). > ((juxt a b c) x) => [(a x) (b x) (c x)]" > ([f] > (fn > ([] [(f)]) > ([x] [(f x)]) > ([x y] [(f x y)]) > ([x y z] [(f x y z)]) > ([x y z & args] [(apply f x y z args)]))) > [ rest of juxt is omitted for brevity ] > > I don't understand why there needs to be a case for [x], [x y], [x y > z] and [x y z & args]. Why not just [args]? And why the magic number > (three) of variables? > > Thomas -- 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 To unsubscribe from this group, send email to clojure+unsubscribegooglegroups.com or reply to this email with the words "REMOVE ME" as the subject.
