functionalscript/types/byte_set/module.f.js

FunctionalScript is a purely functional subset of JavaScript

import { compose } from "../function/module.f.js";
import { reverse, countdown, flat, map } from "../list/module.f.js";
export const has = n => s => ((s >> BigInt(n)) & 1n) === 1n;
// create a set
export const empty = 0n;
//                        0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F
export const universe = 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffn;
export const one = n => 1n << BigInt(n);
export const range = ([b, e]) => one(e - b + 1) - 1n << BigInt(b);
// set operations
export const union = a => b => a | b;
const intersect = a => b => a & b;
export const complement = n => universe ^ n;
const difference = compose(intersect)(compose(complement));
// additional operations
export const set = compose(one)(union);
export const setRange = compose(range)(union);
export const unset = n => s => difference(s)(one(n));
const counter = reverse(countdown(256));
const toRangeMapOp = n => s => i => {
    const current = has(i + 1)(n);
    const prev = has(i)(n);
    return current === prev ? null : [[prev ? [s] : [], i]];
};
export const toRangeMap = n => s => flat(map(toRangeMapOp(n)(s))(counter));