Question

basically, given n, eg 3, how can i create a list of values of all combination of T and F

eg. for n = 3, (make-bools 3) should return ((T T T), (T T F), … (F F F))

This is similar to question Function to return all combinations of n booleans? but to implement in scheme

Answer 1

Not the most efficient:

(define (make-bools n)
  (if (= n 0)
    '()
    (append (addhead 'T (make-bools (- n 1)))
            (addhead 'F (make-bools (- n 1))))))

; Yield copy of l with h added on to head of each list in l
(define (addhead h l)
  (if (null? l)
      l
      (cons (cons h (car l)) (addhead h (cdr l)))))