[wip?] scalaz compiler plugin to guarantee sufficient typeclass definitions #1861
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NeQuissimus
approved these changes
Jun 8, 2018
hobwekiva
approved these changes
Jun 8, 2018
| trait DeriveMap[F[_]] extends ApplicativeClass[F] with MonadClass.Alt[DeriveMap[F]] { | ||
| final override def map[A, B](ma: F[A])(f: (A) => B): F[B] = ap(ma)(pure(f)) | ||
| } | ||
| override def map[A, B](ma: F[A])(f: A => B): F[B] = ap(ma)(pure(f)) |
| trait DerivePmap[F[_]] extends PhantomClass[F] with Alt[DerivePmap[F]] { | ||
| final override def pmap[A, B](ma: F[A]): F[B] = contramap(map(ma)(_ => ()))(_ => ()) | ||
| } | ||
| def pmap[A, B](ma: F[A]): F[B] = contramap(map(ma)(_ => ()))(_ => ()) |
| @@ -17,18 +17,18 @@ trait FiberInstances { | |||
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| implicit def fiberApplicative[E]: Applicative[Fiber[E, ?]] = | |||
| instanceOf(new ApplicativeClass[Fiber[E, ?]] { | |||
| final def pure[A](a: A): Fiber[E, A] = new Fiber[E, A] { | |||
| override def pure[A](a: A): Fiber[E, A] = new Fiber[E, A] { | |||
hobwekiva
reviewed
Jun 12, 2018
| @@ -9,73 +11,32 @@ package types | |||
| * https://typelevel.org/blog/2014/03/09/liskov_lifting.html | |||
| */ | |||
| trait IsCovariantClass[F[_]] { | |||
hobwekiva
reviewed
Jun 12, 2018
| @@ -9,63 +11,32 @@ package types | |||
| * https://typelevel.org/blog/2014/03/09/liskov_lifting.html | |||
| */ | |||
| trait IsContravariantClass[F[_]] { | |||
jbgi
reviewed
Jun 12, 2018
There was a problem hiding this comment.
this is quite nice indeed.
What I liked about previous approach is that it forced users to be conscious of what methods are derived, and with which implementation (ie. all methods are either final or abstract).
But the getting ride of the boilerplate is nice and probably worth it.
| } | ||
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| trait Alt[D <: Alt[D]] | ||
| def flatMap[A, B](ma: M[A])(f: A => M[B]): M[B] = flatten(map(ma)(f)) |
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Could this cause an issue with default impl of map in Monad? ie if one override only flatten then we can have a circular definition between map and flatMap:
def flatMap[A, B](ma: M[A])(f: A => M[B]): M[B] = flatten(map(ma)(f))
def map[A, B](ma: M[A])(f: A => B): M[B] = flatMap(ma)(a => pure(f(a)))this case was checked by the "Alt"-encoding, would be nice to preserve this check.
I think there is some other similar cases as well.
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