fp-ts/lib/Ring.js

Functional programming in TypeScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.getTupleRing = exports.negate = exports.getFunctionRing = void 0;
/**
 * 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
 *
 * @since 2.0.0
 */
var Semiring_1 = require("./Semiring");
/**
 * @category instances
 * @since 2.0.0
 */
function getFunctionRing(ring) {
    var S = Semiring_1.getFunctionSemiring(ring);
    return {
        add: S.add,
        mul: S.mul,
        one: S.one,
        zero: S.zero,
        sub: function (f, g) { return function (x) { return ring.sub(f(x), g(x)); }; }
    };
}
exports.getFunctionRing = getFunctionRing;
/**
 * `negate x` can be used as a shorthand for `zero - x`
 *
 * @since 2.0.0
 */
function negate(ring) {
    return function (a) { return ring.sub(ring.zero, a); };
}
exports.negate = negate;
/**
 * Given a tuple of `Ring`s returns a `Ring` for the tuple
 *
 * @example
 * import { getTupleRing } from 'fp-ts/Ring'
 * import { fieldNumber } from 'fp-ts/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])
 *
 * @category instances
 * @since 2.0.0
 */
function getTupleRing() {
    var rings = [];
    for (var _i = 0; _i < arguments.length; _i++) {
        rings[_i] = arguments[_i];
    }
    return {
        add: function (x, y) { return rings.map(function (R, i) { return R.add(x[i], y[i]); }); },
        zero: rings.map(function (R) { return R.zero; }),
        mul: function (x, y) { return rings.map(function (R, i) { return R.mul(x[i], y[i]); }); },
        one: rings.map(function (R) { return R.one; }),
        sub: function (x, y) { return rings.map(function (R, i) { return R.sub(x[i], y[i]); }); }
    };
}
exports.getTupleRing = getTupleRing;