Refactor for loop to use cond

hy/core/macros.hy

@@ -31,31 +31,6 @@
         [hy._compat [PY33 PY34]])
 
 
-(defmacro for [args &rest body]
-  "shorthand for nested for loops:
-  (for [x foo
-        y bar]
-    baz) ->
-  (for* [x foo]
-    (for* [y bar]
-      baz))"
-
-  (if (odd? (len args))
-    (macro-error args "`for' requires an even number of args."))
-
-  (if (empty? body)
-    (macro-error None "`for' requires a body to evaluate"))
-
-  (if (empty? args)
-    `(do ~@body)
-    (if (= (len args) 2)
-      ; basecase, let's just slip right in.
-      `(for* [~@args] ~@body)
-      ; otherwise, let's do some legit handling.
-      (let [[alist (slice args 0 nil 2)]]
-        `(for* [(, ~@alist) (genexpr (, ~@alist) [~@args])] ~@body)))))
-
-
 (defmacro with [args &rest body]
   "shorthand for nested for* loops:
   (with [[x foo] [y bar]] baz) ->
@@ -113,6 +88,26 @@
   root)
 
 
+(defmacro for [args &rest body]
+  "shorthand for nested for loops:
+  (for [x foo
+        y bar]
+    baz) ->
+  (for* [x foo]
+    (for* [y bar]
+      baz))"
+  (cond 
+   [(odd? (len args))
+    (macro-error args "`for' requires an even number of args.")]
+   [(empty? body)
+    (macro-error None "`for' requires a body to evaluate")]
+   [(empty? args) `(do ~@body)]
+   [(= (len args) 2)  `(for* [~@args] ~@body)]
+   [true 
+    (let [[alist (slice args 0 nil 2)]]
+      `(for* [(, ~@alist) (genexpr (, ~@alist) [~@args])] ~@body))]))
+
+
 (defmacro -> [head &rest rest]
   ;; TODO: fix the docstring by someone who understands this
   (setv ret head)