Support annotations in functions. (google#8)

* Fix error with annotated functions.

Calling inspect.getargspec on an annotated function throws an error in
Python 3. inspect.getfullargspec should be used instead.

* Change if/elif to if/else

if else allows better static analysis.

Author: jgarst

fire/fire_test.py

@@ -98,6 +98,10 @@ def testFirePartialNamedArgsOneMissing(self):
     self.assertEqual(
         fire.Fire(tc.MixedDefaults, 'identity --alpha 1'), (1, '0'))
 
+  def testFireAnnotatedArgs(self):
+    self.assertEqual(fire.Fire(tc.Annotations, 'double 5'), 10)
+    self.assertEqual(fire.Fire(tc.Annotations, 'triple 5'), 15)
+
   def testFireProperties(self):
     self.assertEqual(fire.Fire(tc.TypedProperties, 'alpha'), True)
     self.assertEqual(fire.Fire(tc.TypedProperties, 'beta'), (1, 2, 3))

fire/inspectutils.py

@@ -72,11 +72,18 @@ def GetArgSpec(fn):
   fn, skip_arg = _GetArgSpecFnInfo(fn)
 
   try:
-    argspec = inspect.getargspec(fn)
+
+    if six.PY2:
+      argspec = inspect.getargspec(fn)
+      keywords = argspec.keywords
+    else:
+      argspec = inspect.getfullargspec(fn)
+      keywords = argspec.varkw
+
     args = argspec.args
     defaults = argspec.defaults or ()
     varargs = argspec.varargs
-    keywords = argspec.keywords
+
   except TypeError:
     args = []
     defaults = ()

fire/test_components.py

@@ -75,6 +75,17 @@ def sum(self, alpha=0, beta=0):
   def identity(self, alpha, beta='0'):
     return alpha, beta
 
+class Annotations(object):
+
+  def double(self, count=0):
+    return 2 * count
+
+  def triple(self, count=0):
+    return 3 * count
+
+  double.__annotations__ = {'count': float}
+  triple.__annotations__ = {'count': float}
+
 
 class TypedProperties(object):