Language-Ext 5.0 alpha-1

This release should only be consumed by those who are interested in the new features coming in the monster v5 release.

Just to give you an idea of the scale of this change:

• 193 commits
• 1,836 files changed
• 135,000 lines of code added (!)
• 415,000 lines of code deleted (!!)

It is a monster and should be treated with caution...

• It is not ready for production
• It is not feature complete
• The new features don't have unit tests yet and so are probably full of bugs
• I haven't yet dogfooded all the new functionality, so it may not seem as awesome as it will eventually become!

If you add it to a production project, you should only do so to see (potentially) how many breaking changes there are. I would not advise migrating a production code-base until I get close to the final release.

I am also not going to go into huge detail about the changes here, I will simply list them as headings. I will do a full set of release notes for the beta release. You can however follow the series of articles I am writing to help you all prep for v5 -- it goes (and will go) into much more detail about the features.

New Features

• Higher-kinded traits
  • K<F, A> - higher-kinds enabling interface
  • Includes:
    • Defintions (interfaces listed below)
    • Static modules (Functor.map, Alternative.or, StateM.get, ...)
    • Extension methods (.Map, .Or, Bind, etc.),
    • Extension methods that replace LanguageExt.Transformers (BindT, MapT, etc. ), now fully generic.
    • Trait implementations for all Language-Ext types (Option, Either<L>, etc.)
  • Functor<F>
  • Applicative<F>
  • Monad<M>
  • Foldable<F>
  • Traversable<T>
  • Alternative<F>
  • SemiAlternative<F>
  • Has<M, TRAIT>
  • Reads<M, OUTER_STATE, INNER_STATE>
  • Mutates<M, OUTER_STATE, INNER_STATE>
  • ReaderM<M, Env>
  • StateM<M, S>
  • WriterM<M, OUT>
  • MonadT<M, N> - Monad transformers
    • ReaderT<Env, M, A>
    • WriterT<Out, M, A>
    • StateT<S, M, A>
    • IdentityT<M, A>
    • EitherT<L, M, R>
    • ValidationT<F, M, S>
    • OptionT<M, A>
    • TryT<M, A>
    • IdentityT<M, A>
    • ResourceT<M, A>
• Free<F, A> - Free monads
• IO<A> - new IO monad that is the base for all IO
• Eff<RT, A> monad rewritten to use monad-transformers (StateT<RT, ResourceT<IO>, A>)
• Eff<RT, A> doesn't need HasCancel trait (or any trait)
• Transducers
• Pure / Fail monads
• Lifting
• Improved guards, when, unless
• Nullable annotations - still WIP, mostly complete on Core)
• Collection initialisers

Breaking changes

• netstandard2.0 no longer supported (.NET 8.0+ only)
• Seq1 made [Obsolete]
• 'Trait' types now use static interface methods
• The 'higher-kind' trait types have all been refactored
• The Semigroup<A> and Monoid<A> types have been refactored
• The static TypeClass class has been renamed Trait
• Apply extensions that use raw Func removed
• Manually written Sequence extension methods have been removed
• Manually written Traverse extension methods have been removed
• ToComparer doesn't exist on the Ord<A> trait any more
• Renamed LanguageExt.ClassInstances.Sum
• Guard<E> has become Guard<E, A>
• UnitsOfMeasaure namespace converted to a static class
• Either doesn't support IEnumerable<EitherData> any more
• Either 'bi' functions have their arguments flipped
• Nullable (struct) extensions removed
• Support for Tuple and KeyValuePair removed
• Types removed outright
  • Some<A>
  • OptionNone
  • EitherUnsafe<L, R>
  • EitherLeft<L>
  • EitherRight<L>
  • Validation<MFail, Fail, A>
  • Try<A>
  • TryOption<A>
  • TryAsync<A>
  • TryOptionAsync<A>
  • Result<A>
  • OptionalResult<A>
  • Async extensions for Option<A>
  • ExceptionMatch, ExceptionMatchAsync, ExceptionMatchOptionalAsync
• Libraries removed outright
  • LanguageExt.SysX
  • LanguageExt.CodeGen
  • LanguageExt.Transformers