Version history¶

Breaking: now @pipeline requires a container type when created: @pipeline(Result) or @pipeline(Maybe)

Maybe and Result now has success_type and failure_type aliases

Adds Result.unify utility method for better error type composition

We now support dry-python/classes as a first-class citizen

Adds io_squash to squash several IO containers into one container with a tuple inside, currently works with 9 containers max at a time

Adds untap function which does convert return type to None

Fixes that containers were not usable with multiprocessing

Changes the inheritance order, now BaseContainer is the first child

Fixes that Nothing had incorrect docstrings

Now generated package is protected

Updates poetry to 1.0

Breaking: now pipe() does not require argument to be the first value, instead it is required to use: pipe(f1, f2, f3, f4)(value)

Breaking: dropped everything from returns/__init__.py, because we now have quite a lot of stuff

Breaking: dropped support of zero argument functions for Nothing.fix

Breaking: dropped support of zero argument functions for Nothing.rescue

Maybe now has .failure() to match the same API as Result

Adds identity function

Adds tap function

Now pipe allows to pipe 8 steps

Adds coalesce_result and coalesce_maybe coverters

Fixes that code inside .fix and .rescue of Maybe might be called twice

Now all methods have doctests

Updates docs about Success and _Success, Failure and _Failure

Updates docs about @pipeline

Typechecks async functions and decorators inside typesafety/ tests

Breaking: python>=3.7,<=3.7.2 are not supported anymore, because of a bug inside typing module

Breaking: Now bind does not change the type of an error

Breaking: Now rescue does not change the type of a value

Breaking: Renames map_failure to alt

Adds box() function with the ability to box function for direct container composition like: a -> Container[b] to Container[a] -> Container[b]

Adds IO.lift() function to lift a -> a to IO[a] -> IO[a]

Adds pipe() function to pipeline.py

Adds __hash__() magic methods to all containers

Changes Any to NoReturn in Success and Failure

Now all type parameters in Result, Maybe, and IO are covariant

Massive docs rewrite

Updates mypy version

Updates wemake-python-styleguide and introduces nitpick

Updates pytest-plugin-mypy, all tests now use yml

Provides a bunch of primitive interfaces to write your own containers

Adds .map_failure() method

Adds join() function to join nested containers

Fixes type of Maybe.fix and Maybe.rescue to work with both lambda: 1 and lambda _: 1

Improves README

Reintroduces the Maybe container, typed!

Introduces converters from one type to another

Adds mypy plugin to type decorators

Complete rewrite of Result types

Partial API change, now Success and Failure are not types, but functions

New internal types introduced: FixableContainer and ValueUnwrapContainer

Fixes issue when you could return IO container from Result.bind

Fixes @pipeline return type

Reapplied all types to .py files

Improved docs about IO and Container concept

Adds docs about container composition

Moves from Alpha to Beta

Adds IO marker

Adds unsafe module with unsafe functions

Changes how functions are located inside the project

Fixes container type in @pipeline

Now is_successful is public

Now raise_exception is public

Changes how str() function works for container types

Total rename to “container” in the source code

safe and pipeline now supports asyncio

is_successful now returns Literal types if possible

Adds compose helper function

Adds public API to import returns

Adds raise_exception helper function

Adds full traceback to .unwrap()

Updates multiple dev-dependencies, including mypy

Now search in the docs is working again

Relicenses this project to BSD

Fixes copyright notice in the docs

Moves all types to .pyi files

Renames all classes according to new naming pattern

HUGE improvement of types

Renames fmap to map

Renames do_notation to pipeline, moves it to functions.py

Renames ebind to rescue

Renames efmap to fix

Renames container to Container

Removes Maybe container, since typing does not have NonNullable type

Adds py.typed file to be PEP561 compatible

Adds .pyi files for all modules, to enable mypy support for 3rd party users

Adds Maybe container

Adds immutability and __slots__ to all containers

Adds methods to work with failures

Adds safe decorator to convert exceptions to Result container

Adds is_successful() function to detect if your result is a success

Adds failure() method to unwrap values from failed containers

Changes the type of .bind method for Success container

Changes how equality works, so now Failure(1) != Success(1)

Changes how new instances created on unused methods

Improves docs

Changes how PyPI renders package’s page

Improves README with new badges and installation steps