add partition form to core

the 2 argument version of Clojure's partition.

pre-expand ->> macro in partition

Docstring for partition.

add test-partition

Document partition.

docs/language/core.rst

@@ -674,6 +674,20 @@ Returns ``True`` if *x* is odd. Raises ``TypeError`` if
 
 .. _pos?-fn:
 
+partition
+---------
+
+Usage: ``(partition n coll)``
+
+Chunks coll into tuples of length n. The remainder, if any, is not included.
+
+.. code-block:: hy
+
+   => (list (partition 3 (range 10)))
+   [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
+
+.. _partition-fn:
+
 pos?
 ----
 

hy/core/language.hy

@@ -314,6 +314,10 @@
   (_numeric-check n)
   (= (% n 2) 1))
 
+(defn partition [n coll]
+  "Chunks coll into tuples of length n. The remainder, if any, is not included."
+  (apply zip (* n (, (iter coll)))))
+
 (defn pos? [n]
   "Return true if n is > 0"
   (_numeric_check n)
@@ -423,12 +427,12 @@
         (hyify (. value __name__))
         (catch [] (string value))))))
 
-(def *exports* '[butlast calling-module-name coll? cons cons? cycle
-                 dec distinct disassemble drop drop-last drop-while empty? even?
-                 every? first filter filterfalse flatten float? fraction gensym
-                 identity inc input instance? integer integer? integer-char?
-                 interleave interpose iterable? iterate iterator? keyword
-                 keyword? last list* macroexpand macroexpand-1 map merge-with
-                 name neg? nil? none? nth numeric? odd? pos? range read read-str
-                 remove repeat repeatedly rest reduce second some string string?
-                 symbol? take take-nth take-while zero? zip zip_longest zipwith])
+(def *exports*
+  '[butlast calling-module-name coll? cons cons? cycle dec distinct disassemble
+    drop drop-last drop-while empty? even? every? first filter filterfalse
+    flatten float? fraction gensym identity inc input instance? integer integer?
+    integer-char? interleave interpose iterable? iterate iterator? keyword
+    keyword? last list* macroexpand macroexpand-1 map merge-with name neg? nil?
+    none? nth numeric? odd? partition pos? range read read-str remove repeat
+    repeatedly rest reduce second some string string? symbol? take take-nth
+    take-while zero? zip zip_longest zipwith])

tests/native_tests/core.hy

@@ -470,6 +470,18 @@
   (try (do (odd? None) (assert False))
        (catch [e [TypeError]] (assert (in "not a number" (str e))))))
 
+(defn test-partition []
+  "NATIVE: testing the partition function"
+  (setv ten (range 10))
+  (assert-equal (list (partition 3 ten))
+                [(, 0 1 2) (, 3 4 5) (, 6 7 8)])
+  (assert-equal (list (partition 2 ten))
+                [(, 0 1) (, 2 3) (, 4 5) (, 6 7) (, 8 9)])
+  (assert-equal (list (partition 1 ten))
+                [(, 0) (, 1) (, 2) (, 3) (, 4) (, 5) (, 6) (, 7) (, 8) (, 9)])
+  (assert-equal (list (partition 0 ten)) [])
+  (assert-equal (list (partition -1 ten)) []))
+
 (defn test-pos []
   "NATIVE: testing the pos? function"
   (assert-true (pos? 2))