@implicitNotFound("Could not find an implicit instance of Local[${F}, ${E}]. If you have a\nvalue of type ${E} in scope, or a way of computing one, you may want to construct\na value of type Kleisli for this call-site, rather than type ${F}. An example type:\n\n Kleisli[${F}, ${E}, *]\n\nIf you do not have an ${E} or a way of getting one, you should add\nan implicit parameter of this type to your function. For example:\n\n (implicit flocal: Local[${F}, ${E}])\n") trait Local[F[_], E] extends Ask[F, E] with Serializable
Local[F, E] lets you alter the E value that is observed by an F[A] value
using ask; the modification can only be observed from within that F[A] value.
Local[F, E] lets you alter the E value that is observed by an F[A] value
using ask; the modification can only be observed from within that F[A] value.
Local[F, E] has three external laws:
def askReflectsLocal(f: E => E) = {
local(f)(ask) <-> ask map f
}
def localPureIsPure[A](a: A, f: E => E) = {
local(f)(pure(a)) <-> pure(a)
}
def localDistributesOverAp[A, B](fa: F[A], ff: F[A => B], f: E => E) = {
local(f)(ff ap fa) <-> local(f)(ff) ap local(f)(fa)
}
Local has one internal law:
def scopeIsLocalConst(fa: F[A], e: E) = {
scope(e)(fa) <-> local(_ => e)(fa)
}
- Companion
- object