Solution to Exercise 4.1

[jonathantorres]

function list_of_values_left(exps, env) {
    function loop(exps) {
        if (is_null(exps)) {
            return null;
        }
        return pair(evaluate(head(exps), env), loop(tail(exps)));
    }
    return loop(exps);
}

function list_of_values_right(exps, env) {
    return reverse(list_of_values_left(reverse(exps), env));
}

[EmilyOng]

Sharing an alternative as well :)

// Left-To-Right
function list_of_values(exps, env) {
    return is_null(exps)
        ? null
        : pair(
            evaluate(head(exps), env),
	    list_of_values(tail(exps), env)
        );
}
// Right-To-Left
function list_of_values(exps, env) {
    return is_null(exps)
        ? null
        : append(
            list_of_values(tail(exps), env),
            list(evaluate(head(exps), env))
        );
}