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


instances

getFunctionRing

Signature

export declare function getFunctionRing<A, B>(ring: Ring<B>): Ring<(a: A) => B>

Added in v2.0.0

getTupleRing

Given a tuple of Rings returns a Ring for the tuple

Signature

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

Example

import { getTupleRing } from 'fp-ts/lib/Ring'
import { fieldNumber } from 'fp-ts/lib/Field'

const R = getTupleRing(fieldNumber, fieldNumber, fieldNumber)
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 v2.0.0

type classes

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 function negate<A>(ring: Ring<A>): (a: A) => A

Added in v2.0.0