str_utils2.clj: added partial, with tests

Alternate definition of partial for fns that take their
primary argument first.

2 files changed, 19 insertions, 1 deletions

diff --git a/src/clojure/contrib/str_utils2.clj b/src/clojure/contrib/str_utils2.clj
index 1fbd030d..9a1ea9f7 100644
--- a/src/clojure/contrib/str_utils2.clj
+++ b/src/clojure/contrib/str_utils2.clj
@@ -30,7 +30,7 @@
     http://github.com/francoisdevlin/devlinsf-clojure-utils/"}
  clojure.contrib.str-utils2
  (:refer-clojure :exclude (take replace drop butlast partition
-                           contains? get repeat reverse))
+                           contains? get repeat reverse partial))
  (:import (java.util.regex Pattern)))
 
 
@@ -317,6 +317,19 @@
   [re coll]
   (filter (fn [x] (re-find re (str x))) coll))
 
+(defn partial
+  "Like clojure.core/partial for functions that take their primary
+  argument first.
+
+  Takes a function f and its arguments, NOT INCLUDING the first
+  argument.  Returns a new function whose first argument will be the
+  first argument to f.
+
+  Example: (str-utils2/partial str-utils2/take 2)
+           ;;=> (fn [s] (str-utils2/take s 2))"
+  [f & args]
+  (fn [s & more] (apply f s (concat args more))))
+
 
 ;;; WRAPPERS
 
diff --git a/src/clojure/contrib/test_contrib/str_utils2.clj b/src/clojure/contrib/test_contrib/str_utils2.clj
index 6d1f94d2..ee6aa68e 100644
--- a/src/clojure/contrib/test_contrib/str_utils2.clj
+++ b/src/clojure/contrib/test_contrib/str_utils2.clj
@@ -112,3 +112,8 @@
 
 (deftest t-get
   (is (= \o (s/get "foo" 1))))
+
+(deftest t-partial
+  (is (= "bar" ((s/partial s/drop 3) "foobar")))
+  (is (= "ooba" ((comp (s/partial s/take 4)
+                       (s/partial s/drop 1)) "foobar"))))