Swiftz

Swiftz is a Swift library for functional programming.

It defines purely functional data structures and functions.

Implemented:

• Control/Base functions
• Maybe<A> with Equatable and Comparable
• Num typeclass
• Semigroup<A> and Monoid<A> with some instances

Typechecks but currently impossible:

• Either<A, B> with Equatable
• List<A>

Note:

The "currently impossible" data structures we think the language intends to support.

Not realised:

These abstractions require language features that Swift does not support yet.

• Either<A, B> crashes with unimplemented IRGen feature! non-fixed multi-payload enum layout. rdar://17109392
• List<A> by an enum crashes the compiler. rdar://???
• List<A> via a super class and 2 sub classes crashes with unimplemented IRGen feature! non-fixed class layout. rdar://17109323
• Functor, Applicative, Monad, Comonad. To enable these, a higher kind, C++ template-template, or Scala-like kind system is needed. rdar://???

General notes:

• enum should derive Equatable and Comparable if possible, similar to case classes in Scala. Or a deriving mechanic like generics should be present. rdar://???