console.log([1, 2, 3].map(elem => elem - 2))？（part 1）

lambda-calculus-1.js

function array(lt) {
    let pair = l => r => f => f(l)(r);
    let left = p => p(l => r => l);
    let right = p => p(l => r => r);

    let nil = pair(undefined)(undefined);
    let con = head => tail => pair(head)(tail);
    let head = lt => left(lt)
    let tail = lt => right(lt);

    let isEmpty = lt => head(lt) === undefined;

    function arr(acc, l) {
        if(isEmpty(l)) {
            return acc;
        } else {
            return arr(acc.concat([head(l)]), tail(l));
        }
    }
    return arr([], lt);
}
/* 
底下相當於 console.log([1, 2, 3].map(elem => elem - 1))，願意的話，試著挑戰看看，將 :?、數值、加、減、比較等，都轉換為 lambda ...XD
*/

console.log(array((f => (x => f(n => x(x)(n)))(x => f(n => x(x)(n))))(map => lt => f => (lt => (lt => (p => p(l => r => l))(lt))(lt) === undefined)(lt) ? ((l => r => f => f(l)(r))(undefined)(undefined)) : (head => tail => (l => r => f => f(l)(r))(head)(tail))(f((lt => (p => p(l => r => l))(lt))(lt)))(map((lt => (p => p(l => r => r))(lt))(lt))(f)))((elems => (lt => (f => (x => f(n => x(x)(n)))(x => f(n => x(x)(n))))(rev => r => l => (lt => (lt => (p => p(l => r => l))(lt))(lt) === undefined)(l) ? r : rev((head => tail => (l => r => f => f(l)(r))(head)(tail))((lt => (p => p(l => r => l))(lt))(l))(r))((lt => (p => p(l => r => r))(lt))(l)))((l => r => f => f(l)(r))(undefined)(undefined))(lt))(elems()))((f => (x => f(n => x(x)(n)))(x => f(n => x(x)(n))))(rcon => tail => head => head === undefined ? tail : rcon((head => tail => (l => r => f => f(l)(r))(head)(tail))(head)(tail)))((l => r => f => f(l)(r))(undefined)(undefined))(1)(2)(3)))(elem => elem - 1)));