Annotations-0.2: Constructing, analyzing and destructing annotated trees

Portabilitynon-portable
Stabilityexperimental
Maintainergenerics@haskell.org
Safe HaskellSafe-Infered

Annotations.MultiRec.Zipper

Contents

Description

The generic zipper.

Synopsis

Locations

data Loc whereSource

Abstract type of locations. A location contains the current focus and its context. A location is parameterized over the family of datatypes and over the type of the complete value.

Constructors

Loc :: phi ix -> r ix -> Ctxs phi f ix r a -> Loc phi f r a 

Instances

Zipper phi f => HFunctor phi (Loc phi f) 

Context frames

data family Ctx f :: * -> (* -> *) -> * -> *Source

Abstract type of context frames. Not required for the high-level navigation functions.

data Ctxs whereSource

Constructors

Empty :: Ctxs phi f a r a 
Push :: phi ix -> Ctx f b r ix -> Ctxs phi f ix r a -> Ctxs phi f b r a 

Instances

Zipper phi f => HFunctor phi (Ctxs phi f b) 

Generic zipper class

class HFunctor phi f => Zipper phi f whereSource

It is in general not necessary to use the generic navigation functions directly. The functions listed in the `Interface' section below are more user-friendly.

Methods

cmapA :: Applicative a => (forall ix. phi ix -> r ix -> a (r' ix)) -> phi ix -> Ctx f b r ix -> a (Ctx f b r' ix)Source

fill :: phi b -> Ctx f b r ix -> r b -> f r ixSource

first, last :: (forall b. phi b -> r b -> Ctx f b r ix -> a) -> f r ix -> Maybe aSource

next, prev :: (forall b. phi b -> r b -> Ctx f b r ix -> a) -> phi b -> Ctx f b r ix -> r b -> Maybe aSource

Instances

Zipper phi U 
Zipper phi (K a) 
El phi xi => Zipper phi (I xi) 
(Constructor c, Zipper phi f) => Zipper phi (C c f) 
Zipper phi f => Zipper phi (:>: f xi) 
(Zipper phi f, Zipper phi g) => Zipper phi (:*: f g) 
(Zipper phi f, Zipper phi g) => Zipper phi (:+: f g) 

Interface

enter :: Zipper phi f => phi ix -> r ix -> Loc phi f r ixSource

Start navigating a datastructure. Returns a location that focuses the entire value and has an empty context.

on :: (forall xi. phi xi -> r xi -> a) -> Loc phi f r ix -> aSource

Operate on the current focus. This function can be used to extract the current point of focus.

update :: (forall xi. phi xi -> r xi -> r xi) -> Loc phi f r ix -> Loc phi f r ixSource

Update the current focus without changing its type.