Add minimal typing support and fix py3.10

.travis.yml

@@ -1,30 +1,22 @@
 
 language: python
 python:
-    - "pypy"
     - "pypy3"
 matrix:
   include:
-      - { python: '2.7', env: }
-      - { arch: arm64, python: '2.7' }
-      - { python: '3.4', env: }
-      - { python: '3.5', env: }
       - { python: '3.6', env: }
       - { python: '3.7', env: }
       - { python: '3.8', env: }
-      - { arch: arm64, python: '3.8' }
+      - { python: '3.9', env: }
+      - { arch: arm64, python: '3.9' }
 install:
     - pip install --upgrade pip
     - pip install coverage
     - pip install --upgrade pytest pytest-benchmark
 
 script:
     - |
-      if [[ $(bc <<< "$TRAVIS_PYTHON_VERSION >= 3.3") -eq 1 ]]; then
-         py.test --doctest-modules multipledispatch
-      else
-         py.test --doctest-modules --ignore=multipledispatch/tests/test_dispatcher_3only.py multipledispatch
-      fi
+      py.test --doctest-modules multipledispatch
 
 after_success:
     - |

multipledispatch/dispatcher.py

@@ -1,3 +1,4 @@
+from typing import Any, Callable, Generic, Optional, Tuple, TypeVar, get_type_hints
 from warnings import warn
 import inspect
 from .conflict import ordering, ambiguities, super_signature, AmbiguityWarning
@@ -95,7 +96,10 @@ def variadic_signature_matches(types, full_signature):
     return all(variadic_signature_matches_iter(types, full_signature))
 
 
-class Dispatcher(object):
+DISPATCHED_RETURN = TypeVar("DISPATCHED_RETURN")
+
+
+class Dispatcher(Generic[DISPATCHED_RETURN]):
     """ Dispatch methods based on type signature
 
     Use ``dispatch`` to add implementations
@@ -119,14 +123,16 @@ class Dispatcher(object):
     """
     __slots__ = '__name__', 'name', 'funcs', '_ordering', '_cache', 'doc'
 
-    def __init__(self, name, doc=None):
+    def __init__(self, name: str, doc: Optional[None] = None) -> None:
         self.name = self.__name__ = name
         self.funcs = {}
         self.doc = doc
 
         self._cache = {}
 
-    def register(self, *types, **kwargs):
+    def register(
+        self, *types: type, **kwargs: Any
+    ) -> Callable[[Callable[..., DISPATCHED_RETURN]], Callable[..., DISPATCHED_RETURN]]:
         """ register dispatcher with new implementation
 
         >>> f = Dispatcher('f')
@@ -171,19 +177,19 @@ def get_func_annotations(cls, func):
         if params:
             Parameter = inspect.Parameter
 
-            params = (param for param in params
-                      if param.kind in
-                      (Parameter.POSITIONAL_ONLY,
-                       Parameter.POSITIONAL_OR_KEYWORD))
-
+            hints = get_type_hints(func)
             annotations = tuple(
-                param.annotation
-                for param in params)
+                hints.get(param.name, Parameter.empty)
+                for param in params
+                if param.kind in (
+                    Parameter.POSITIONAL_ONLY, Parameter.POSITIONAL_OR_KEYWORD
+                )
+            )
 
             if all(ann is not Parameter.empty for ann in annotations):
                 return annotations
 
-    def add(self, signature, func):
+    def add(self, signature: Tuple[type, ...], func: Callable[..., DISPATCHED_RETURN]) -> None:
         """ Add new types/method pair to dispatcher
 
         >>> D = Dispatcher('add')
@@ -263,7 +269,7 @@ def reorder(self, on_ambiguity=ambiguity_warn):
             on_ambiguity(self, amb)
         return od
 
-    def __call__(self, *args, **kwargs):
+    def __call__(self, *args: Any, **kwargs: Any) -> DISPATCHED_RETURN:
         types = tuple([type(arg) for arg in args])
         try:
             func = self._cache[types]

multipledispatch/tests/test_core.py

@@ -1,14 +1,15 @@
-from multipledispatch import dispatch
+from multipledispatch import dispatch as orig_dispatch
 from multipledispatch.utils import raises
 from functools import partial
+import pytest
 
-test_namespace = dict()
 
-orig_dispatch = dispatch
-dispatch = partial(dispatch, namespace=test_namespace)
+@pytest.fixture(name="dispatch")
+def fixture_dispatch():
+    return partial(orig_dispatch, namespace=dict())
 
 
-def test_singledispatch():
+def test_singledispatch(dispatch):
     @dispatch(int)
     def f(x):
         return x + 1
@@ -28,7 +29,7 @@ def f(x):
     assert raises(NotImplementedError, lambda: f('hello'))
 
 
-def test_multipledispatch(benchmark):
+def test_multipledispatch(dispatch):
     @dispatch(int, int)
     def f(x, y):
         return x + y
@@ -48,7 +49,7 @@ class D(C): pass
 class E(C): pass
 
 
-def test_inheritance():
+def test_inheritance(dispatch):
     @dispatch(A)
     def f(x):
         return 'a'
@@ -62,7 +63,7 @@ def f(x):
     assert f(C()) == 'a'
 
 
-def test_inheritance_and_multiple_dispatch():
+def test_inheritance_and_multiple_dispatch(dispatch):
     @dispatch(A, A)
     def f(x, y):
         return type(x), type(y)
@@ -78,7 +79,7 @@ def f(x, y):
     assert raises(NotImplementedError, lambda: f(B(), B()))
 
 
-def test_competing_solutions():
+def test_competing_solutions(dispatch):
     @dispatch(A)
     def h(x):
         return 1
@@ -90,7 +91,7 @@ def h(x):
     assert h(D()) == 2
 
 
-def test_competing_multiple():
+def test_competing_multiple(dispatch):
     @dispatch(A, B)
     def h(x, y):
         return 1
@@ -102,7 +103,7 @@ def h(x, y):
     assert h(D(), B()) == 2
 
 
-def test_competing_ambiguous():
+def test_competing_ambiguous(dispatch):
     @dispatch(A, C)
     def f(x, y):
         return 2
@@ -115,7 +116,7 @@ def f(x, y):
     # assert raises(Warning, lambda : f(C(), C()))
 
 
-def test_caching_correct_behavior():
+def test_caching_correct_behavior(dispatch):
     @dispatch(A)
     def f(x):
         return 1
@@ -129,7 +130,7 @@ def f(x):
     assert f(C()) == 2
 
 
-def test_union_types():
+def test_union_types(dispatch):
     @dispatch((A, C))
     def f(x):
         return 1
@@ -156,7 +157,7 @@ def foo(x):
 
 """
 Fails
-def test_dispatch_on_dispatch():
+def test_dispatch_on_dispatch(dispatch):
     @dispatch(A)
     @dispatch(C)
     def q(x):
@@ -167,7 +168,7 @@ def q(x):
 """
 
 
-def test_methods():
+def test_methods(dispatch):
     class Foo(object):
         @dispatch(float)
         def f(self, x):
@@ -188,7 +189,7 @@ def g(self, x):
     assert foo.g(1) == 4
 
 
-def test_methods_multiple_dispatch():
+def test_methods_multiple_dispatch(dispatch):
     class Foo(object):
         @dispatch(A, A)
         def f(x, y):

multipledispatch/tests/test_dispatcher_3only.py

@@ -17,6 +17,10 @@ def inc(x: int):
     def inc(x: float):
         return x - 1
 
+    @f.register()
+    def inc(x: 'float'):
+        return x - 1
+
     assert f(1) == 2
     assert f(1.0) == 0.0