python-effect · manishtomar · May 27, 2015
diff --git a/effect/_sync.py b/effect/_sync.py
@@ -63,3 +63,28 @@ def sync_wrapper(*args):
        except:
            box.fail(sys.exc_info())
    return sync_wrapper
+
+
+def effect_performer(f):
+    """
+    A decorator for performers that return effect
+
+    The function being decorated is expected to take a dispatcher and an intent
+    (and not a box), and should return (dispatcher, effect) tuple. The returned
+    effect will be performed using returned dispatcher.
+
+    Example::
+
+        @effect_performer
+        def perform_foo(dispatcher, foo):
+            new_disp = ComposedDispatcher(
+                [special_dispatcher(foo.fields), dispatcher])
+            return new_disp, foo.effect
+    """
+    @wraps(f)
+    def eff_wrapper(*args):
+        box = args[-1]
+        pass_args = args[:-1]
+        new_disp, eff = f(*pass_args)
+        perform(new_disp, eff, eff.on(box.succeed, box.fail))
+    return eff_wrapper