Copyright	(C) MLabs 2025
License	Apache 2.0
Maintainer	koz@mlabs.city, sean@mlabs.city
Safe Haskell	None
Language	Haskell2010

Covenant.Zipper

Contents

Types
Functions
- Actions
- Elimination

Description

A read-only zipper for the Covenant ASG, based on an action monad.

Since: 1.3.0

Synopsis

data ZipperAction
data Tape a b = Tape [a] b [a]
data ZipperState where
- pattern WorkingZipper :: [Tape Ref Id] -> Tape Ref (Either Arg (Id, ASGNode)) -> ZipperState
- pattern BrokenZipper :: ZipperState
data ASGZipper a
moveUp :: ZipperAction
moveDown :: ZipperAction
moveLeft :: ZipperAction
moveRight :: ZipperAction
resetZipper :: ZipperAction
runASGZipper :: ASG -> ASGZipper a -> a

Types

data ZipperAction Source #

A requested movement from the zipper. To build these, use dedicated smart constructors in this module. You can 'chain together' ZipperAction using the Semigroup instance.

Since: 1.3.0

Instances

Instances details

Monoid ZipperAction Source #

Since: 1.3.0

Instance details

Defined in Covenant.Zipper

Methods

mempty :: ZipperAction #

mappend :: ZipperAction -> ZipperAction -> ZipperAction #

mconcat :: [ZipperAction] -> ZipperAction #

Semigroup ZipperAction Source #

Since: 1.3.0

Instance details

Defined in Covenant.Zipper

Methods

(<>) :: ZipperAction -> ZipperAction -> ZipperAction #

sconcat :: NonEmpty ZipperAction -> ZipperAction #

stimes :: Integral b => b -> ZipperAction -> ZipperAction #

Action ZipperAction Source #

Since: 1.3.0

Instance details

Defined in Covenant.Zipper

Associated Types

type StateOf ZipperAction
Instance details Defined in Covenant.Zipper type StateOf ZipperAction = ZipperState

Methods

act :: ZipperAction -> Endo (StateOf ZipperAction) Source #

MonadUpdate ZipperAction ASGZipper Source #

Since: 1.3.0

Instance details

Defined in Covenant.Zipper

Methods

send :: ZipperAction -> ASGZipper (StateOf ZipperAction) Source #

update :: ZipperAction -> ASGZipper () Source #

request :: ASGZipper (StateOf ZipperAction) Source #

type StateOf ZipperAction Source #

Instance details

Defined in Covenant.Zipper

type StateOf ZipperAction = ZipperState

data Tape a b Source #

A 'list with a focus', which may be of a different type to the rest. The first field is 'backwards', in that its first element is actually the furthest from the focus. Thus, if we have Tape [3, 2, 1] "foo" [4, 5], the 'list' actually looks like this:

[1, 2, 3, "foo", 4, 5]

but not like this:

[3, 2, 1, "foo", 4, 5]

Since: 1.3.0

Constructors

Tape [a] b [a]

Instances

Instances details

Functor (Tape a) Source #	Since: 1.3.0
Instance details Defined in Covenant.Zipper Methods fmap :: (a0 -> b) -> Tape a a0 -> Tape a b # (<$) :: a0 -> Tape a b -> Tape a a0 #

data ZipperState where Source #

The current state of the zipper, including whether it's in a broken state or not, and if not in a broken state, the current position and the path taken to get here.

Since: 1.3.0

Bundled Patterns

pattern WorkingZipper :: [Tape Ref Id] -> Tape Ref (Either Arg (Id, ASGNode)) -> ZipperState

Matches on a working zipper, giving access to a stack of Tapes representing the path taken to get here (tracking sibling positions) and the current position, with the focus at either an Arg or an ASGNode.

Parent positions use Id for the focus, as Args cannot have descendants.

Since: 1.3.0

pattern BrokenZipper :: ZipperState

Matches on a zipper in a broken state.

Since: 1.3.0

data ASGZipper a Source #

A 'zipper command monad', designed to traverse an ASG. Based on an action monad.

To perform zipper moves, use send together with a ZipperAction. If you want to find out something about where we're standing, use request, together with pattern matching on ZipperState.

Since: 1.3.0

Instances

Instances details

Applicative ASGZipper Source #	Since: 1.3.0
Instance details Defined in Covenant.Zipper Methods pure :: a -> ASGZipper a # (<>) :: ASGZipper (a -> b) -> ASGZipper a -> ASGZipper b # liftA2 :: (a -> b -> c) -> ASGZipper a -> ASGZipper b -> ASGZipper c # (>) :: ASGZipper a -> ASGZipper b -> ASGZipper b # (<*) :: ASGZipper a -> ASGZipper b -> ASGZipper a #
Functor ASGZipper Source #	Since: 1.3.0
Instance details Defined in Covenant.Zipper Methods fmap :: (a -> b) -> ASGZipper a -> ASGZipper b # (<$) :: a -> ASGZipper b -> ASGZipper a #
Monad ASGZipper Source #	Since: 1.3.0
Instance details Defined in Covenant.Zipper Methods (>>=) :: ASGZipper a -> (a -> ASGZipper b) -> ASGZipper b # (>>) :: ASGZipper a -> ASGZipper b -> ASGZipper b # return :: a -> ASGZipper a #
MonadUpdate ZipperAction ASGZipper Source #	Since: 1.3.0
Instance details Defined in Covenant.Zipper Methods send :: ZipperAction -> ASGZipper (StateOf ZipperAction) Source # update :: ZipperAction -> ASGZipper () Source # request :: ASGZipper (StateOf ZipperAction) Source #

Functions

Actions

moveUp :: ZipperAction Source #

Move towards the source of the ASG, 'back up' along the path taken to reach the current position. Will put the zipper in a broken state if used at the source node.

Since: 1.3.0

moveDown :: ZipperAction Source #

Move to the leftmost child of the current position. Will put the zipper in a broken state if used at a sink node.

Since: 1.3.0

moveLeft :: ZipperAction Source #

Move to the sibling immediately to the left of the current position. Will put the zipper in a broken state if used at a leftmost sibling.

Since: 1.3.0

moveRight :: ZipperAction Source #

Move to the sibling immediately to the right of the current position. Will put the zipper in a broken state if used at a rightmost sibling.

Since: 1.3.0

resetZipper :: ZipperAction Source #

If the zipper is currently in a broken state, reset it to the last position it was at before breaking. Otherwise, this does nothing.

Since: 1.3.0

Elimination

runASGZipper :: ASG -> ASGZipper a -> a Source #

Perform the stated actions to traverse over the ASG given by the argument.

Since: 1.3.0