Adds .alt and .fix methods, refs #274

Author: sobolevn

returns/_generated/pointfree/alt.pyi

@@ -2,7 +2,11 @@ from typing import Callable, TypeVar, overload
 
 from typing_extensions import Protocol
 
-from returns.context import RequiresContextIOResult, RequiresContextResult
+from returns.context import (
+    RequiresContextFutureResult,
+    RequiresContextIOResult,
+    RequiresContextResult,
+)
 from returns.future import FutureResult
 from returns.io import IOResult
 from returns.result import Result
@@ -37,6 +41,15 @@ class _Altable(Protocol[_ErrorType, _NewErrorType]):
     ) -> RequiresContextIOResult[_EnvType, _ValueType, _NewErrorType]:
         ...
 
+    @overload
+    def __call__(
+        self,
+        container: RequiresContextFutureResult[
+            _EnvType, _ValueType, _ErrorType,
+        ],
+    ) -> RequiresContextFutureResult[_EnvType, _ValueType, _NewErrorType]:
+        ...
+
     @overload
     def __call__(
         self,

returns/_generated/pointfree/fix.pyi

@@ -2,7 +2,11 @@ from typing import Callable, TypeVar, overload
 
 from typing_extensions import Protocol
 
-from returns.context import RequiresContextIOResult, RequiresContextResult
+from returns.context import (
+    RequiresContextFutureResult,
+    RequiresContextIOResult,
+    RequiresContextResult,
+)
 from returns.future import FutureResult
 from returns.io import IOResult
 from returns.result import Result
@@ -37,6 +41,15 @@ class _Fixable(Protocol[_ErrorType, _NewValueType]):
     ) -> RequiresContextIOResult[_EnvType, _NewValueType, _ErrorType]:
         ...
 
+    @overload
+    def __call__(
+        self,
+        container: RequiresContextFutureResult[
+            _EnvType, _ValueType, _ErrorType,
+        ],
+    ) -> RequiresContextFutureResult[_EnvType, _NewValueType, _ErrorType]:
+        ...
+
     @overload
     def __call__(
         self,

returns/context/requires_context_future_result.py

@@ -202,6 +202,68 @@ def bind(
             ),
         )
 
+    def fix(
+        self, function: Callable[[_ErrorType], _NewValueType],
+    ) -> 'RequiresContextFutureResult[_EnvType, _NewValueType, _ErrorType]':
+        """
+        Composes failed container with a pure function.
+
+        .. code:: python
+
+          >>> import anyio
+          >>> from returns.context import RequiresContextFutureResult
+          >>> from returns.io import IOSuccess
+
+          >>> assert anyio.run(
+          ...     RequiresContextFutureResult.from_value(1).fix(
+          ...        lambda x: x + 1,
+          ...     ),
+          ...     RequiresContextFutureResult.empty,
+          ... ) == IOSuccess(1)
+
+          >>> assert anyio.run(
+          ...     RequiresContextFutureResult.from_failure(1).fix(
+          ...        lambda x: x + 1,
+          ...     ),
+          ...     RequiresContextFutureResult.empty,
+          ... ) == IOSuccess(2)
+
+        """
+        return RequiresContextFutureResult(
+            lambda deps: self(deps).fix(function),
+        )
+
+    def alt(
+        self, function: Callable[[_ErrorType], _NewErrorType],
+    ) -> 'RequiresContextFutureResult[_EnvType, _ValueType, _NewErrorType]':
+        """
+        Composes failed container with a pure function.
+
+        .. code:: python
+
+          >>> import anyio
+          >>> from returns.context import RequiresContextFutureResult
+          >>> from returns.io import IOSuccess, IOFailure
+
+          >>> assert anyio.run(
+          ...     RequiresContextFutureResult.from_value(1).alt(
+          ...        lambda x: x + 1,
+          ...     ),
+          ...     RequiresContextFutureResult.empty,
+          ... ) == IOSuccess(1)
+
+          >>> assert anyio.run(
+          ...     RequiresContextFutureResult.from_failure(1).alt(
+          ...        lambda x: x + 1,
+          ...     ),
+          ...     RequiresContextFutureResult.empty,
+          ... ) == IOFailure(2)
+
+        """
+        return RequiresContextFutureResult(
+            lambda deps: self(deps).alt(function),
+        )
+
     def rescue(
         self,
         function: Callable[

typesafety/test_context/test_requires_context_future_result/test_requires_context_future_result.yml

@@ -46,6 +46,32 @@
     reveal_type(x.rescue(test))  # N: Revealed type is 'returns.context.requires_context_future_result.RequiresContextFutureResult[builtins.str, builtins.int, builtins.bool*]'
 
 
+- case: requires_context_future_result_fix
+  disable_cache: true
+  main: |
+    from returns.context import RequiresContextFutureResult
+
+    x: RequiresContextFutureResult[str, int, float]
+
+    def test(param: float) -> bool:
+        ...
+
+    reveal_type(x.fix(test))  # N: Revealed type is 'returns.context.requires_context_future_result.RequiresContextFutureResult[builtins.str, builtins.bool*, builtins.float]'
+
+
+- case: requires_context_future_result_alt
+  disable_cache: true
+  main: |
+    from returns.context import RequiresContextFutureResult
+
+    x: RequiresContextFutureResult[str, int, float]
+
+    def test(param: float) -> bool:
+        ...
+
+    reveal_type(x.alt(test))  # N: Revealed type is 'returns.context.requires_context_future_result.RequiresContextFutureResult[builtins.str, builtins.int, builtins.bool*]'
+
+
 - case: requires_context_future_result_value_or
   disable_cache: true
   main: |

typesafety/test_pointfree/test_alt.yml

@@ -113,6 +113,19 @@
     reveal_type(alt(test)(x))  # N: Revealed type is 'returns.context.requires_context_ioresult.RequiresContextIOResult[builtins.bool*, builtins.str*, builtins.int]'
 
 
+- case: alt_requires_context_future_result
+  disable_cache: true
+  main: |
+    from returns.pointfree import alt
+    from returns.context import RequiresContextFutureResult
+
+    def test(arg: float) -> int:
+        ...
+
+    x: RequiresContextFutureResult[bool, str, float]
+    reveal_type(alt(test)(x))  # N: Revealed type is 'returns.context.requires_context_future_result.RequiresContextFutureResult[builtins.bool*, builtins.str*, builtins.int]'
+
+
 - case: alt_futureresult
   disable_cache: true
   main: |

typesafety/test_pointfree/test_fix.yml

@@ -115,6 +115,19 @@
     reveal_type(fix(test)(x))  # N: Revealed type is 'returns.context.requires_context_ioresult.RequiresContextIOResult[builtins.bool*, builtins.int, builtins.float]'
 
 
+- case: fix_requires_context_future_result
+  disable_cache: true
+  main: |
+    from returns.pointfree import fix
+    from returns.context import RequiresContextFutureResult
+
+    def test(arg: float) -> int:
+        ...
+
+    x: RequiresContextFutureResult[bool, str, float]
+    reveal_type(fix(test)(x))  # N: Revealed type is 'returns.context.requires_context_future_result.RequiresContextFutureResult[builtins.bool*, builtins.int, builtins.float]'
+
+
 - case: fix_futureresult
   disable_cache: true
   main: |