制御構造禁止プログラミング

// 末尾再帰の最適化はブラウザ上のJavaScriptでは基本的に行われないため、スタックオーバーフローが発生します
/**
 * @param {number} n 
 * @param {Function} f 
 * @returns 0
 */
const fFor1 = (n, f) => {
    if (n <= 0) return n;
    f(n - 1);
    return fFor1(n - 1, f);
};
console.log("> " + fFor1(5, n => console.log(n)));
 
/**
 * @param {number} from 
 * @param {number} to
 * @param {Function} f
 * @returns to
 */
const fFor2 = (from, to, f) => {
    if (from >= to) return from;
    f(from);
    return fFor2(from + 1, to, f);
};
console.log("> " + fFor2(2, 6, n => console.log(n)));
 
/**
 * @param {number} initialization 
 * @param {Function} condition predicate
 * @param {Function} afterthought 
 * @param {Function} f
 * @returns The last value that was not operated on by f
 */
const fFor3 = (initialization, condition, afterthought, f) => {
    if (!condition(initialization)) return initialization;
    f(initialization);
    return fFor3(afterthought(initialization), condition, afterthought, f);
};
console.log("> " + fFor3(10, n => n < 15, n => ++n, n => console.log(n)));
 
const fWhile = (condition, f) => {
    if (!condition(f())) return;
    fWhile(condition, f);
};