generic: new module functor

1 files changed, 38 insertions, 0 deletions

diff --git a/src/clojure/contrib/generic/functor.clj b/src/clojure/contrib/generic/functor.clj
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+++ b/src/clojure/contrib/generic/functor.clj
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+;; Generic interface for functors
+
+;; by Konrad Hinsen
+;; last updated March 18, 2009
+
+;; Copyright (c) Konrad Hinsen, 2009. All rights reserved.  The use
+;; and distribution terms for this software are covered by the Eclipse
+;; Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+;; which can be found in the file epl-v10.html at the root of this
+;; distribution.  By using this software in any fashion, you are
+;; agreeing to be bound by the terms of this license.  You must not
+;; remove this notice, or any other, from this software.
+
+(ns clojure.contrib.generic.functor
+  "Generic functor interface")
+
+
+(defmulti fmap
+  "Applies function f to each item in the data structure s and returns
+   a structure of the same kind."
+   {:arglists '([f s])}
+   (fn [f s] (type s)))
+
+(defmethod fmap clojure.lang.ISeq
+  [f s]
+  (map f s))
+
+(defmethod fmap clojure.lang.IPersistentVector
+  [f v]
+  (into (empty v) (map f v)))
+
+(defmethod fmap clojure.lang.IPersistentMap
+  [f m]
+  (into (empty m) (for [[k v] m] [k (f v)])))
+
+(defmethod fmap clojure.lang.IPersistentSet
+  [f s]
+  (into (empty s) (map f s)))