Add zipwith

docs/language/api.rst

@@ -1250,3 +1250,20 @@ infinite series without consuming infinite amount of memory.
     ...  (while True (yield (.randint random low high))))
     => (list-comp x [x (take 15 (random-numbers 1 50))])])
     [7, 41, 6, 22, 32, 17, 5, 38, 18, 38, 17, 14, 23, 23, 19]
+
+zipwith
+-------
+
+`zipwith` zips multiple lists and maps the given function over the result. It is equilavent to calling `zip`, followed by calling `map` on the result.
+
+In the following example, `zipwith` is used to add the contents of two lists together. The equilavent `map` and `zip` calls follow.
+
+.. code-block:: clj
+   
+   => (import operator.add)
+   
+   => (zipwith operator.add [1 2 3] [4 5 6])   ; using zipwith
+   [5, 7, 9]
+   
+   => (map operator.add (zip [1 2 3] [4 5 6])) ; using map+zip
+   [5, 7, 9]

hy/core/language.hy

@@ -345,10 +345,16 @@
   (_numeric_check n)
   (= n 0))
 
+(defn zipwith [func &rest lists]
+  "Zip the contents of several lists and map a function to the result"
+  (do
+    (import functools)
+    (map (functools.partial (fn [f args] (apply f args)) func) (apply zip lists))))
+
 (def *exports* '[calling-module-name coll? cons cons? cycle dec distinct
                  disassemble drop drop-while empty? even? every? first filter
                  flatten float? gensym identity inc instance? integer
                  integer? integer-char? iterable? iterate iterator?
                  list* macroexpand macroexpand-1 neg? nil? none? nth
                  numeric? odd? pos? remove repeat repeatedly rest second
-                 some string string? take take-nth take-while zero?])
+                 some string string? take take-nth take-while zero? zipwith])

hy/core/macros.hy

@@ -199,3 +199,4 @@
           (.append ret
                    `(setv ~name ~main)))
     ret))
+

tests/native_tests/core.hy

@@ -470,3 +470,12 @@
   (assert-equal res [None None])
   (setv res (list (take-while (fn [x] (not (none? x))) [1 2 3 4 None 5 6 None 7])))
   (assert-equal res [1 2 3 4]))
+
+(defn test-zipwith []
+  "NATIVE: testing the zipwith function"
+  (import operator)
+  (setv res (zipwith operator.add [1 2 3] [3 2 1]))
+  (assert-equal (list res) [4 4 4])
+  (setv res (zipwith operator.sub [3 7 9] [1 2 4]))
+  (assert-equal (list res) [2 5 5]))
+