| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
ApNormalize.DList
Contents
Description
This structure is part of the definition of Aps.
Synopsis
- newtype ApDList f a = ApDList (forall r. Yoneda f (a -> r) -> f r)
- liftApDList :: Applicative f => f a -> ApDList f a
- lowerApDList :: Yoneda f (b -> c) -> ApDList f b -> f c
- newtype Yoneda f a = Yoneda (forall x. (a -> x) -> f x)
Applicative difference lists
Type of applicative difference lists.
An applicative transformer which accumulates f-actions in
a left-nested composition using (.<*>)
ApDList represents a sequence of f-actions
u1 :: f x1, ... un :: f xn as "term with a hole"
(_ <*> u1 <*> ... <*> un) :: f r.
That hole must have type _ :: f (x1 -> ... -> un -> r);
the variable number of arrows is hidden by existential quantification
and continuation passing.
To help ensure that syntactic invariant,
the Functor and Applicative instances for ApDList have no constraints.
liftApDList is the only function whose signature requires an
Applicative fu inside one (.<*>)
liftApDList :: Applicative f => f a -> ApDList f a Source #
A difference list with one element u, denoted _ <*> u.
lowerApDList :: Yoneda f (b -> c) -> ApDList f b -> f c Source #
Complete a difference list, filling the hole with the first argument.