Overview

Provides a pointed array, which is a non-empty zipper-like array structure that tracks an index (focus) position in an array. Focus can be moved forward and backwards through the array.

The array [1, 2, 3, 4] with focus on 3 is represented by new Zipper([1, 2], 3, [4])

Adapted from

• https://github.com/DavidHarrison/purescript-list-zipper
• https://github.com/thunklife/purescript-zipper
• https://github.com/scalaz/scalaz/blob/series/7.3.x/core/src/main/scala/scalaz/Zipper.scala

Table of contents

• URI (type alias)
• Zipper (class)
  • update (method)
  • modify (method)
  • toArray (method)
  • isOutOfBound (method)
  • move (method)
  • up (method)
  • down (method)
  • start (method)
  • end (method)
  • insertLeft (method)
  • insertRight (method)
  • deleteLeft (method)
  • deleteRight (method)
  • map (method)
  • ap (method)
  • reduce (method)
  • inspect (method)
  • toString (method)
• URI (constant)
• zipper (constant)
• fromArray (function)
• fromNonEmptyArray (function)
• getMonoid (function)
• getSemigroup (function)

URI (type alias)

Signature

export type URI = typeof URI

Zipper (class)

Signature

export class Zipper<A> {
  constructor(readonly lefts: Array<A>, readonly focus: A, readonly rights: Array<A>) { ... }
  ...
}

Added in v1.9.0

update (method)

Update the focus in this zipper.

Signature

update(a: A): Zipper<A> { ... }

Added in v1.9.0

modify (method)

Apply f to the focus and update with the result.

Signature

modify(f: (a: A) => A): Zipper<A> { ... }

Added in v1.9.0

toArray (method)

Signature

toArray(): Array<A> { ... }

Added in v1.9.0

isOutOfBound (method)

Signature

isOutOfBound(index: number): boolean { ... }

Added in v1.9.0

move (method)

Moves focus in the zipper, or None if there is no such element.

Signature

move(f: (currentIndex: number) => number): Option<Zipper<A>> { ... }

Added in v1.9.0

up (method)

Signature

up(): Option<Zipper<A>> { ... }

Added in v1.9.0

down (method)

Signature

down(): Option<Zipper<A>> { ... }

Added in v1.9.0

start (method)

Moves focus to the start of the zipper.

Signature

start(): Zipper<A> { ... }

Added in v1.9.0

end (method)

Moves focus to the end of the zipper.

Signature

end(): Zipper<A> { ... }

Added in v1.9.0

insertLeft (method)

Inserts an element to the left of focus and focuses on the new element.

Signature

insertLeft(a: A): Zipper<A> { ... }

Added in v1.9.0

insertRight (method)

Inserts an element to the right of focus and focuses on the new element.

Signature

insertRight(a: A): Zipper<A> { ... }

Added in v1.9.0

deleteLeft (method)

Deletes the element at focus and moves the focus to the left. If there is no element on the left, focus is moved to the right.

Signature

deleteLeft(): Option<Zipper<A>> { ... }

Added in v1.9.0

deleteRight (method)

Deletes the element at focus and moves the focus to the right. If there is no element on the right, focus is moved to the left.

Signature

deleteRight(): Option<Zipper<A>> { ... }

Added in v1.9.0

map (method)

Signature

map<B>(f: (a: A) => B): Zipper<B> { ... }

Added in v1.9.0

ap (method)

Signature

ap<B>(fab: Zipper<(a: A) => B>): Zipper<B> { ... }

Added in v1.9.0

reduce (method)

Signature

reduce<B>(b: B, f: (b: B, a: A) => B): B { ... }

Added in v1.9.0

inspect (method)

Signature

inspect(): string { ... }

toString (method)

Signature

toString(): string { ... }

URI (constant)

Signature

export const URI = ...

zipper (constant)

Signature

export const zipper: Applicative1<URI> & Foldable2v1<URI> & Traversable2v1<URI> & Comonad1<URI> = ...

Added in v1.9.0

fromArray (function)

Signature

export const fromArray = <A>(as: Array<A>, focusIndex: number = 0): Option<Zipper<A>> => ...

Added in v1.9.0

fromNonEmptyArray (function)

Signature

export const fromNonEmptyArray = <A>(nea: NonEmptyArray<A>): Zipper<A> => ...

Added in v1.9.0

getMonoid (function)

Signature

export const getMonoid = <A>(M: Monoid<A>): Monoid<Zipper<A>> => ...

Added in v1.9.0

getSemigroup (function)

Signature

export const getSemigroup = <A>(S: Semigroup<A>): Semigroup<Zipper<A>> => ...

Added in v1.9.0