End of refactoring

monads/future.py

@@ -63,9 +63,6 @@ class Future(Monad[T]):
 
     __rshift__ = bind
 
-    def __and__(
-        self, other: Awaitable[Callable[[T], S]]
-    ) -> Future[S]:  # pragma: no cover
-        return Future.apply(self, other)
+    __and__ = lambda other, self: Future.apply(self, other)  # type: ignore
 
     __mul__ = __rmul__ = map

monads/list.py

@@ -22,6 +22,7 @@ class List(Monad[T], Monoidal[list]):
         return List(list(map(function, self.value)))
 
     def apply(self, functor: List[Callable[[T], S]]) -> List[S]:
+
         return List(
             list(chain.from_iterable([map(f, self.value) for f in functor.value]))
         )
@@ -37,10 +38,10 @@ class List(Monad[T], Monoidal[list]):
         def mcons(acc: List[_List[T]], x: List[T]) -> List[_List[T]]:
             return acc.bind(lambda acc_: x.map(lambda x_: acc_ + [x_]))
 
-        return reduce(mcons, xs, List.mzero())
+        empty: List[_List[T]] = List.pure([])
+        return reduce(mcons, xs, empty)
 
-    def __and__(self, other: List[Callable[[T], S]]) -> List[S]:  # pragma: no cover
-        return List.apply(self, other)
+    __and__ = lambda other, self: List.apply(self, other)  # type: ignore
 
     def mappend(self, other: List[T]) -> List[T]:
         return List(self.value + other.value)

monads/maybe.py

@@ -86,8 +86,7 @@ class Maybe(Monad[T]):
         else:
             return Nothing()
 
-    def __and__(self, other: Maybe[Callable[[T], S]]) -> Maybe[S]:  # pragma: no cover
-        return Maybe.apply(self, other)
+    __and__ = lambda other, self: Maybe.apply(self, other)  # type: ignore
 
     __rshift__ = bind
     __mul__ = __rmul__ = map

monads/reader.py

@@ -58,7 +58,8 @@ class Reader(Monad[T], Generic[Env, T]):
         def mcons(acc: Reader[Env, List[T]], x: Reader[Env, T]) -> Reader[Env, List[T]]:
             return acc.bind(lambda acc_: x.map(lambda x_: acc_ + [x_]))
 
-        empty: Reader[Env, List[T]] = cls.pure([])
+        empty_list: List[T] = []
+        empty: Reader[Env, List[T]] = Reader.pure(empty_list)
         return reduce(mcons, xs, empty)
 
     def __eq__(self, other: object):  # pragma: no cover
@@ -70,6 +71,7 @@ class Reader(Monad[T], Generic[Env, T]):
         signature = inspect.signature(self)
         return f"<Reader {module}.{name}{signature}>"
 
+    __and__ = lambda other, self: Reader.apply(self, other)  # type: ignore
+
     __mul__ = __rmul__ = map
     __rshift__ = bind
-    __and__ = lambda other, self: Reader.apply(self, other)

monads/result.py

@@ -60,7 +60,7 @@ class Result(Monad[T], Generic[T, E]):
         def mcons(acc: Result[List[T], E], x: Result[T, E]) -> Result[List[T], E]:
             return acc.bind(lambda acc_: x.map(lambda x_: acc_ + [x_]))
 
-        empty: Result[List[T], E] = cls.pure([])
+        empty: Result[List[T], E] = Result.pure([])
         return functools.reduce(mcons, xs, empty)
 
     def withDefault(self, default: T) -> T:
@@ -89,8 +89,9 @@ class Result(Monad[T], Generic[T, E]):
         else:
             return None
 
+    __and__ = lambda other, self: Result.apply(self, other)  # type: ignore
+
     __rshift__ = bind
-    __and__ = lambda other, self: Result.apply(self, other)
     __mul__ = __rmul__ = map
 
 

setup.cfg

@@ -3,3 +3,6 @@ test=pytest
 
 [tool:pytest]
 addopts = --black --mypy --cov monads --cov-report xml:reports/coverage.xml
+
+[mypy-tests]
+ignore_errors = True

tests/test_applicatives.py

@@ -18,4 +18,5 @@ def test_apply_and_operator(monad) -> None:
     subtract: Callable[[int], Callable[[int], int]] = lambda x: lambda y: x - y
     ten = monad.pure(10)
     six = monad.pure(6)
-    assert six.apply(ten.map(subtract)) == subtract * ten & six
+    functor = ten.map(subtract)
+    assert six.apply(functor) == subtract * ten & six

tests/test_currying.py

@@ -28,12 +28,15 @@ def test_curried_function_annotation_drops_arguments_as_it_is_applied() -> None:
     def add3(a: int, b: int, c: int) -> int:
         return a + b + c
 
-    assert inspect.Signature(
-        [
-            inspect.Parameter(
-                param, inspect.Parameter.POSITIONAL_OR_KEYWORD, annotation=int
-            )
-            for param in ["b", "c"]
-        ],
-        return_annotation=int,
-    ) == inspect.signature(curry(add3)(1))
+    assert (
+        inspect.Signature(
+            [
+                inspect.Parameter(
+                    param, inspect.Parameter.POSITIONAL_OR_KEYWORD, annotation=int
+                )
+                for param in ["b", "c"]
+            ],
+            return_annotation=int,
+        )
+        == inspect.signature(curry(add3)(1))
+    )