Implement yield-from in Python 2.x as a macro

And who said you can't teach an old dog new tricks.

  ... but at the same time, drop Python 3.2 for not knowing this new
  trick.

.travis.yml

@@ -3,7 +3,6 @@ python:
   - "pypy"
   - "2.6"
   - "2.7"
-  - "3.2"
   - "3.3"
   - "3.4"
 cache:

hy/core/macros.hy

@@ -179,6 +179,25 @@
             ~@body))))
 
 
+(if-python2
+  (defmacro/g! yield-from [expr]
+    `(do (import types)
+         (setv ~g!iter (iter ~expr))
+         (setv ~g!return nil)
+         (setv ~g!message nil)
+         (while true
+           (try (if (isinstance ~g!iter types.GeneratorType)
+                  (setv ~g!message (yield (.send ~g!iter ~g!message)))
+                  (setv ~g!message (yield (next ~g!iter))))
+           (catch [~g!e StopIteration]
+             (do (setv ~g!return (if (hasattr ~g!e "value")
+                                     (. ~g!e value)
+                                     nil))
+               (break)))))
+           ~g!return))
+  nil)
+
+
 (defmacro defmain [args &rest body]
   "Write a function named \"main\" and do the if __main__ dance"
   (let [[retval (gensym)]]

make.bat

@@ -87,7 +87,7 @@ goto :EOF
 if "%1" == "tox" (
 :tox
     call :venv
-    tox -e "py26,py27,py32,py33,flake8"
+    tox -e "py26,py27,py33,py34,flake8"
 goto :EOF
 )
 

tests/native_tests/native_macros.hy

@@ -233,5 +233,13 @@
   (assert (= (tda-a2) :bazinga))
   (assert (= tda-main tda-a1 tda-a2)))
 
+(defn test-yield-from []
+ "NATIVE: testing yield from"
+  (defn yield-from-test []
+    (for* [i (range 3)]
+       (yield i))
+       (yield-from [1 2 3]))
+  (assert (= (list (yield-from-test)) [0 1 2 1 2 3])))
+
 (defn test-botsbuildbots []
   (assert (> (len (first (Botsbuildbots))) 50)))

tests/native_tests/py3_only_tests.hy

@@ -4,21 +4,6 @@
 (import [hy._compat [PY33]])
 (import [hy.errors [HyCompileError]])
 
-(defn test-yield-from []
- "NATIVE: testing yield from"
-
- (try
-  (eval
-   '(do (defn yield-from-test []
-          (for* [i (range 3)]
-            (yield i))
-          (yield-from [1 2 3]))
-        (assert (= (list (yield-from-test)) [0 1 2 1 2 3]))))
-  (catch [e HyCompileError]
-    ;; Yield-from is supported in py3.3+ only
-    (assert (not PY33)))
-  (else (assert PY33))))
-
 
 
 (defn test-exception-cause []

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py26,py27,pypy,py32,py33,flake8
+envlist = py26,py27,pypy,py33,flake8
 skipsdist = True
 
 [testenv]