Returns

Features

- **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` converters

Bugfixes

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

Misc

- 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

Features

- **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

Bugfixes

- Changes `Any` to `NoReturn` in `Success` and `Failure`
- Now all type parameters in `Result`, `Maybe`, and `IO` are covariant

Misc

- Massive docs rewrite
- Updates `mypy` version
- Updates `wemake-python-styleguide` and introduces `nitpick`
- Updates `pytest-plugin-mypy`, all tests now use `yml`

Features

- Provides a bunch of primitive interfaces to write your own containers
- Adds `.map_failure()` method
- Adds `flatten()` function to join nested containers

Bugfixes

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

Misc

- Improves `README`

Features

- 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`

Bugfixes

- Fixes issue when you could return `IO` container from `Result.bind`
- Fixes `pipeline` return type

Misc

- Reapplied all types to `.py` files
- Improved docs about `IO` and `Container` concept
- Adds docs about container composition
- Moves from `Alpha` to `Beta`

Features

- Adds `IO` container
- Adds `unsafe` module with unsafe functions
- Changes how functions are located inside the project

Bugfixes

- Fixes container type in `pipeline`
- Now `is_successful` is public
- Now `raise_exception` is public

Misc

- Changes how `str()` function works for container types
- Total rename to "container" in the source code

Features

- `safe` and `pipeline` now supports `asyncio`
- `is_successful` now returns `Literal` types if possible