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fp-ts

Ring overview

The Ring class is for types that support addition, multiplication, and subtraction operations.

Instances must satisfy the following law in addition to the Semiring laws:

  • Additive inverse: a - a <-> (zero - a) + a <-> zero

Adapted from https://github.com/purescript/purescript-prelude/blob/master/src/Data/Ring.purs

Added in v2.0.0

Table of contents

model

Ring (interface)

Signature

export interface Ring<A> extends Semiring<A> {
  readonly sub: (x: A, y: A) => A
}

Added in v2.0.0

utils

negate

negate x can be used as a shorthand for zero - x

Signature

export declare const negate: <A>(R: Ring<A>) => (a: A) => A

Added in v2.0.0

tuple

Given a tuple of Rings returns a Ring for the tuple

Signature

export declare const tuple: <A extends readonly unknown[]>(
  ...rings: { [K in keyof A]: Ring<A[K]> }
) => Ring<Readonly<A>>

Example

import { tuple } from 'fp-ts/Ring'
import * as N from 'fp-ts/number'

const R = tuple(N.Field, N.Field, N.Field)
assert.deepStrictEqual(R.add([1, 2, 3], [4, 5, 6]), [5, 7, 9])
assert.deepStrictEqual(R.mul([1, 2, 3], [4, 5, 6]), [4, 10, 18])
assert.deepStrictEqual(R.one, [1, 1, 1])
assert.deepStrictEqual(R.sub([1, 2, 3], [4, 5, 6]), [-3, -3, -3])
assert.deepStrictEqual(R.zero, [0, 0, 0])

Added in v2.10.0

zone of death

getFunctionRing

Use getRing instead.

Signature

export declare const getFunctionRing: <A, B>(R: Ring<B>) => Ring<(a: A) => B>

Added in v2.0.0

getTupleRing

Use tuple instead.

Signature

export declare const getTupleRing: <T extends readonly Ring<any>[]>(
  ...rings: T
) => Ring<{ [K in keyof T]: T[K] extends Ring<infer A> ? A : never }>

Added in v2.0.0