Version 0.17.0

Features

• Python3.10 support
• Enables Pattern Matching support for Result containers
• Enables Pattern Matching support for Maybe container
• Enables Pattern Matching support for IOResult container
• Improves hypothesis plugin, now we detect
  when type cannot be constructed and give a clear error message

Version 0.16.0

Features

• Makes _Nothing a singleton
• Refactor flow function to be faster

Bugfixes

• Fixes that assert_trace was not catching containers
  from @safe-wrapped functions

Misc

• Fixes typos in documentation

Version 0.15.0 aka The initial HKT release

Features

• Adds Higher Kinded Types partial support

• Breaking: drops python3.6 support

• Breaking: makes our mypy plugin not optional, but required!

• Breaking: changes all RequiresContext-based type arguments order,
  previously we used to specify _EnvType as the first type argument,
  now it is the last one. This is done to respect new HKT rules

• Breaking: renames .rescue to .lash

• Breaking: removes all old interfaces from primitives/interfaces.py,
  use new typeclasses instead

• Breaking: Maybe is fully reworked to be lawful

• Breaking: removes value_or pointfree method,
  because it is impossible to express with HKT

• Breaking: removes .value_or, .unwrap, and .failure methods
  from FutureResult and RequiresContext-based types,
  because we do require these methods to raise an exception on failure,
  but these methods were lazy and did not raise the required exception

• Breaking: changes how is_successful is typed:
  now we allow any Unwrappable interface instances there,
  including custom ones

• Breaking: changes UnwrapFailedError constructor,
  now it does accept an Unwrappable instance instead of a BaseContainer

• Breaking: removes .fix method from all containers,
  also removes fix pointfree function

• Breaking: Removes coalesce function,
  because it is impossible to properly type it

• Breaking: Removes all Context* based types with .ask() method,
  use new .ask() methods on the Reader-based containers

• Breaking: Now Future and FutureResult can be awaited multiple times

• Breaking: Removes .unify() method from several containers,
  use unify() pointfree function instead

• Breaking: Removes .from_iterable method from all containers,
  instead adds better iterables support,
  we now have returns.iterables module with Fold helper

• Breaking: Renames property empty to no_args of
  all RequiresContext-based classes

• Adds new public interfaces: see returns.interfaces

• Adds methods package with several helpful things inside

• Adds FutureSuccess and FutureFailure unit functions
  to be similar to Result and IOResult

• Adds .swap method to Result, IOResult, FutureResult,
  and other result based containers

• Adds .modify_env method to all RequiresContext* types

• Adds .rescue to Maybe

• Adds .equals methods to types that can be compared directly:
  Result, Maybe, IO, IOResult

• Adds missing from_requires_context_future_result to RequiresContext

• Adds .from_optional and .bind_optional to Maybe container

• Adds __slots__ to UnwrapFailedError with halted_container

• Changes flatten to work with KindN and any possible container

• Adds a helper to test traces to our pytest plugin

• Adds cond function to pointfree and methods packages

• Adds compose_result HKT method and pointfree function

• Adds unify HKT pointfree function

• Adds bimap pointfree function

• Adds unwrap_or_failure function to methods package

• Adds collect_trace helper function for better development experience

• Adds hypothesis intergration and pre-defined "monad laws as values"

• Adds assert_equal method to our pytest plugin

Bugfixes

• Breaking: fixes serious typing issue and changes how flow works
• Breaking: fixes serious typing issue and changes how pipe works,
  now it has a hard limit of 20 parameters
• Fixes that RequiresContextFutureResult was not supported by pytest plugin
• Fixes incorrect partial behaviour in an edge case, #618
• Fixes that .apply method of IOResult was working incorrectly,
  it was returning IOFailure(2)
  as a result of IOFailure(1).apply(IOFailure(2))
• Fixes bug that safe(tap(...)) was revealing invalid types sometimes

Misc

• Adds a lot of new typetests
• Checks that now all math laws are checked for all types
• Changes docs structure, adds new Interfaces, HKT, and Methods pages
• Changed __str__ method in BaseContainer class to __repr__ method
• Adds Quickstart guide

Version 0.14.0

Special thanks to:

• @orsinium
• @thedrow
• @thepabloaguilar
• and other (code and ideas) contributors
  for making this release possible. You are awesome!

Announcement: https://sobolevn.me/2020/06/how-async-should-have-been

Features

• Breaking: renames mypy plugin from decorator_plugin to returns_plugin
  because of a complete rewrite and lots of new features

• Breaking: changes @safe, @impure, impure_safe, @maybe semantics:
  they do not work with async functions anymore;
  now you are forced to use Future and its helpers
  to work with async functions

• Breaking: renames Maybe.new to Maybe.from_value.
  Because all our other containers support this protocol.
  Only Maybe was different, sorry for that!

• Breaking: renames .from_success() to .from_value(),
  there's no need in two separate methods

• Breaking: renames .from_successful_io() to .from_io(),
  there's no need in two separate methods

• Breaking: renames .from_successful_context() to .from_context(),
  there's no need in two separate methods

• Breaking: since we now support .apply() method,
  there's no more need in *_squash converters, they are removed

• Breaking: renamed Instanceable to Applicative

• Breaking: changes .from_io and .from_failed_io of IOResult
  to return Any instead of NoReturn unfilled type

• Breaking: removes .lift and .lift_* methods from all containers,
  use map_, bind_result, bind_io, and other pointfree helpers instead

• Breaking: removes @pipeline function. It was a mistake:
  it does not work with mixed container types,
  it does not type failures properly,
  it does not work with IO and Future,
  it enforces to write imperative code in a functional codebase.
  Use flow instead

• Adds typed partial and curry mypy plugins!

• Adds typed flow plugin, now it can accept any number of arguments,
  it now also has excelent type inference

• Adds typed pipe plugin, now it can accept any number of arguments,
  it now also has good type inference

• Adds managed pipeline function that is useful
  for working with stateful computations

• Adds typed map_, fix, and alt pointfree functions

• Adds typed bind_result, bind_io, bind_ioresult,
  bind_context, bind_context_result, bind_future,
  bind_async, and bind_awaitable pointfree functions

• Adds typed bind_async_future and bind_async_future_result
  pointfree functions

• Adds typed unify pointfree function

• Adds typed apply pointfree function

• Adds typed value_or pointfree function

• Adds pytest plugin with the ability to tests error handling

• Adds Future container to easily work with async functions

• Adds FutureResult container to easily work
  with async function that might fail

• Adds RequiresContextFutureResult container

• Adds ReaderFutureResult alias for RequiresContextFutureResult

• Adds RequiresContextFutureResultE and ReaderFutureResultE aliases

• Adds Future, FutureResult and RequiresContextFutureResult
  support for all existing pointfree functions

• Adds bind_io method to IOResult

• Adds bind_io method to RequiresContextIOResult

• Adds or_else method to Maybe

• Adds .from_io and .from_failed_io to RequiresContextIOResult

• Syncs naming in from_* methods, now all parameters are named inner_value

• Adds not_ composition helper

• Adds flatten support for Future,
  FutureResult and RequiresContextFutureResult

• Adds __copy__ and __deepcopy__ magic methods to Immutable class

• Speeds up is_successful function

• Makes all Context context helpers abstract,
  so you cannot create new instances of this class,
  also adds __slots__ to these classes

• Improves RequiresContext* types with NoDeps where it is logically true

Bugfixes

• Fixes that @safe decorator was generating incorrect signatures
  for functions with Any
• Fixes that .rescue() of RequiresContextResult was returning Any
• Fixes that .rescue() of RequiresContextIOResult was returning Any
• Fixes that RequiresContextResult and RequiresContextIOResult
  were not final
• Fixes that ImmutableStateError was not a subclass of AttributeError
• Fixes that IOResult was not showing str representation
  of wrapped inner_value

Misc

• Replaces pytest-asyncio with anyio plugin,
  now we test compatibility with any IO stack: asyncio, trio, curio
• Updates lots of dependencies
• Adds lots of new tests
• Updates lots of docs
• Removes "IO marker" name from docs in favor for "IO container",
  it is not special at all. Why would we call it differently?

Version 0.13.0

Announcing article: https://sobolevn.me/2020/02/typed-functional-dependency-injection

Features

• Breaking: renames join to flatten, sorry!

• Breaking: renames box to bind and moves it to returns.pointfree

• Breaking: removes Maybe.rescue and Maybe.fix methods

• Breaking: renames io_squash to squash_io
  and moves it to returns.converters

• Breaking: moves all interfaces from returns.primitives.container to
  returns.primitives.interfaces

• Adds rescue pointfree function

• Adds ResultE alias for Result[..., Exception]

• Adds RequiresContext container and Context helper class

• Adds RequiresContext support for bind pointfree function

• Adds RequiresContext support for flatten function

• Adds RequiresContextResult container

• Adds RequiresContextResultE alias

• Adds ReaderResult and ReaderResultE aliases
  for RequiresContextResult[..., ..., Exception]

• Adds RequiresContextResult support for bind and rescue

• Adds RequiresContextResult support for flatten

• Adds IOResult helper to work better with IO[Result[a, b]]

• Adds IOResultE alias for IOResult[a, Exception]

• Adds IOResult support for bind

• Adds IOResult support for flatten

• Adds IOResult support for @pipeline

• Adds IOResult support for coalesce

• Adds IOResult support for is_successful

• Adds RequiresContextIOResult container

• Adds RequiresContextIOResultE alias

• Adds ReaderIOResult and ReaderIOResultE aliases
  for RequiresContextIOResult[..., ..., Exception]

• Adds RequiresContextIOResult support for bind and rescue

• Adds RequiresContextIOResult support for flatten

• Adds Result.lift, Maybe.lift, RequiresContext.lift,
  and RequiresContextResult.lift functions in addition to IO.lift

• Adds Immutable primitive type

• Adds Unitable protocol and .from_success() and .from_failure()
  methods for all Result realted classes

• Adds Instanceable protocol and .from_value() method
  for IO and RequiresContext

• Adds flow function, which is similar to pipe

• Adds swap coverter for Result and IOResult

• Adds squash_context function to squash RequiresContext similar to IO

Bugfixes

• Now Success and Failure (both io and pure) return Any and not NoReturn
• Fixes how flatten works, also adds more tests and docs about Failure case
• Fixes Unwrappable type being parametrized with only one TypeVar
• Changes Success and Failure to return Any instead of NoReturn

Misc

• Updates poetry version in travis
• Imporves pipe docs with lambda and Generic problem
• Improves docs in several places
• Now examples in docs tries to be docstests where possible
• Changes how tests are checked with mypy in CI

Version 0.12.0

Features

• 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

Bugfixes

• Fixes that containers were not usable with multiprocessing
• Changes the inheritance order, now BaseContainer is the first child
• Fixes that Nothing had incorrect docstrings

Misc

• Now generated package is protected
• Updates poetry to 1.0

Version 0.11.0

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 coverters

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

Version 0.10.0

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

Version 0.9.0

Features

• Provides a bunch of primitive interfaces to write your own containers
• Adds .map_failure() method
• Adds join() 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

Version 0.8.0

Features

• Reintroduces the Maybe monad, 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