@@ -4,12 +4,10 @@ ;; It turns out that my original implementation of remove-if would trash the stack with very large lists. This can be verified by (on my setup at least) with `(remove-if even? (range 1000000))`. After digesting some tips from [Chouser](http://chouser.n01se.net/), I chose to rewrite the function using [recur](http://clojure.org/special_forms#toc10) and [lazy-cons](http://clojure.org/api#toc277). However, I have to admit that the documentation for both was ... spartan. ; <pre lang="lisp"> -(defn remove-if [f lst] - (if (seq lst) ; idiomatic - (if (f (first lst)) - (recur f (rest lst)) - (lazy-cons (first lst) (remove-if f (rest lst)))) - nil)) +(defn remove-if + "Remove elements from a sequence coll if they satisfy a predicate f" + [coll f] + (filter (complement f) coll)) (remove-if even? (range 1000000)) ; go get some coffee... unless you have an Azul system ; </pre> reading/onlisp/chapter2-redux.clj 242c3c97413df144707a7f8363b6eaa86525eddc Fogus mefogus@gmail.com http://github.com/fogus/polyglot/commit/c4b58f7c9b506a347fdb6c2ab1ebd641b0a51369 c4b58f7c9b506a347fdb6c2ab1ebd641b0a51369 2009-05-10T17:53:15-07:00 2009-05-10T17:53:15-07:00 Updating On Lisp -> Clojure code to reflect Clojure 1.0-isms ba7fc041d3b503bb8227001235113420bd271092 Fogus mefogus@gmail.com