functor-combo-0.0.7: Functor combinators with tries & zippers

FunctorCombo.ZipperFix

Description

Zippers for functor fixpoints

Synopsis

type Context f = [Der f (Fix f)]Source

Context for functor fixpoints

Context for a regular type

type Zipper f = (Context f, Fix f)Source

Zipper for a functor tree. Also called "location"

up :: Holey f => Zipper f -> Zipper fSource

Move upward. Error if empty context.

up' :: Holey f => Zipper f -> Maybe (Zipper f)Source

Variant of up. Nothing if empty context.

up

Nothing

down :: Holey f => Zipper f -> f (Zipper f)Source