Support Python 3.6+

Author: RazerM

docs/source/conf.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 #
 # Documentation build configuration file, created by
 # sphinx-quickstart on Sat Jan 21 19:11:14 2017.

setup.py

@@ -1,20 +1,13 @@
-# coding: utf-8
-from __future__ import absolute_import, division, print_function
-
-from io import open
-
 from setuptools import find_packages, setup
 
 version = dict()
 
-# read _version.py as bytes, otherwise exec will complain about
-# 'coding: utf-8', which we want there for the normal Python 2 import
-with open('src/outcome/_version.py', 'rb') as fp:
+with open('src/outcome/_version.py') as fp:
     version_mod = fp.read()
 
 exec(version_mod, version)
 
-LONG_DESC = open('README.rst', encoding='utf-8').read()
+LONG_DESC = open('README.rst').read()
 
 setup(
     name='outcome',
@@ -33,7 +26,7 @@
     packages=find_packages('src'),
     package_dir={'': 'src'},
     install_requires=['attrs>=19.2.0'],
-    python_requires='>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*',
+    python_requires='>=3.6',
     keywords='result',
     classifiers=[
         'Development Status :: 5 - Production/Stable',
@@ -44,10 +37,9 @@
         'Operating System :: POSIX :: Linux',
         'Operating System :: MacOS :: MacOS X',
         'Operating System :: Microsoft :: Windows',
-        'Programming Language :: Python :: 2.7',
-        'Programming Language :: Python :: 3.4',
-        'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
     ],

src/outcome/__init__.py

@@ -1,20 +1,12 @@
-# coding: utf-8
 """Top-level package for outcome."""
-from __future__ import absolute_import, division, print_function
-
-import sys
 
+from ._impl import Error, Outcome, Value, acapture, capture
 from ._util import AlreadyUsedError, fixup_module_metadata
 from ._version import __version__
 
-if sys.version_info >= (3, 5):
-    from ._async import Error, Outcome, Value, acapture, capture
-    __all__ = (
-        'Error', 'Outcome', 'Value', 'acapture', 'capture', 'AlreadyUsedError'
-    )
-else:
-    from ._sync import Error, Outcome, Value, capture
-    __all__ = ('Error', 'Outcome', 'Value', 'capture', 'AlreadyUsedError')
+__all__ = (
+    'Error', 'Outcome', 'Value', 'acapture', 'capture', 'AlreadyUsedError'
+)
 
 fixup_module_metadata(__name__, globals())
 del fixup_module_metadata

src/outcome/_async.py

@@ -1,13 +1,10 @@
-# coding: utf-8
-from __future__ import absolute_import, division, print_function
-
 import abc
 
 import attr
 
-from ._util import ABC, AlreadyUsedError, remove_tb_frames
+from ._util import AlreadyUsedError, remove_tb_frames
 
-__all__ = ['Error', 'Outcome', 'Value', 'capture']
+__all__ = ['Error', 'Outcome', 'Value', 'acapture', 'capture']
 
 
 def capture(sync_fn, *args, **kwargs):
@@ -17,15 +14,30 @@ def capture(sync_fn, *args, **kwargs):
       Either a :class:`Value` or :class:`Error` as appropriate.
 
     """
+    # _sync.capture references ErrorBase and ValueBase
     try:
         return Value(sync_fn(*args, **kwargs))
     except BaseException as exc:
         exc = remove_tb_frames(exc, 1)
         return Error(exc)
 
 
+async def acapture(async_fn, *args, **kwargs):
+    """Run ``await async_fn(*args, **kwargs)`` and capture the result.
+
+    Returns:
+      Either a :class:`Value` or :class:`Error` as appropriate.
+
+    """
+    try:
+        return Value(await async_fn(*args, **kwargs))
+    except BaseException as exc:
+        exc = remove_tb_frames(exc, 1)
+        return Error(exc)
+
+
 @attr.s(repr=False, init=False, slots=True)
-class Outcome(ABC):
+class Outcome(abc.ABC):
     """An abstract class representing the result of a Python computation.
 
     This class has two concrete subclasses: :class:`Value` representing a
@@ -69,6 +81,17 @@ def send(self, gen):
 
         """
 
+    @abc.abstractmethod
+    async def asend(self, agen):
+        """Send or throw the contained value or exception into the given async
+        generator object.
+
+        Args:
+          agen: An async generator object supporting ``.asend()`` and
+              ``.athrow()`` methods.
+
+        """
+
 
 @attr.s(frozen=True, repr=False, slots=True)
 class Value(Outcome):
@@ -80,7 +103,7 @@ class Value(Outcome):
     """The contained value."""
 
     def __repr__(self):
-        return 'Value({!r})'.format(self.value)
+        return f'Value({self.value!r})'
 
     def unwrap(self):
         self._set_unwrapped()
@@ -90,6 +113,10 @@ def send(self, gen):
         self._set_unwrapped()
         return gen.send(self.value)
 
+    async def asend(self, agen):
+        self._set_unwrapped()
+        return await agen.asend(self.value)
+
 
 @attr.s(frozen=True, repr=False, slots=True)
 class Error(Outcome):
@@ -101,7 +128,7 @@ class Error(Outcome):
     """The contained exception object."""
 
     def __repr__(self):
-        return 'Error({!r})'.format(self.error)
+        return f'Error({self.error!r})'
 
     def unwrap(self):
         self._set_unwrapped()
@@ -113,3 +140,7 @@ def unwrap(self):
     def send(self, it):
         self._set_unwrapped()
         return it.throw(self.error)
+
+    async def asend(self, agen):
+        self._set_unwrapped()
+        return await agen.athrow(self.error)

src/outcome/_sync.py renamed to src/outcome/_impl.py

@@ -1,7 +1,3 @@
-# coding: utf-8
-from __future__ import absolute_import, division, print_function
-
-import abc
 import sys
 
 
@@ -25,17 +21,7 @@ def fix_one(obj):
 
 
 def remove_tb_frames(exc, n):
-    if sys.version_info < (3,):
-        return exc
     tb = exc.__traceback__
     for _ in range(n):
         tb = tb.tb_next
     return exc.with_traceback(tb)
-
-
-if sys.version_info < (3,):
-
-    class ABC(object):
-        __metaclass__ = abc.ABCMeta
-else:
-    ABC = abc.ABC

src/outcome/_util.py

@@ -1,4 +1,3 @@
-# coding: utf-8
 # This file is imported from __init__.py and exec'd from setup.py
 
 __version__ = "1.0.1"

src/outcome/_version.py

@@ -1,4 +1,3 @@
 pytest
 pytest-cov
-pytest-asyncio; python_version >= '3.5'
-async-generator; python_version >= '3.5'
+pytest-asyncio

test-requirements.txt

@@ -1,2 +0,0 @@
-# coding: utf-8
-from __future__ import absolute_import, division, print_function

tests/__init__.py

@@ -1,6 +1,3 @@
-# coding: utf-8
-from __future__ import absolute_import, division, print_function
-
 import sys
 
 import pytest