Trivia map implementation in scheme (really stupid and slow)

map.rkt

(define first car)
(define second cadr)
(define rest cdr)
(define (third list) (car (cddr list)))
(define fourth cadddr)

(define initmap '())

(define test
  (list (list 'a 1) (list 'b 3))
  )

(define (lookup map key default)
  (cond
    ((eq? '() map) default)
    ((eq? (first (first map)) key) (second (first map)))
    (#t (lookup (rest map) key default))
    )
  )

(define (add map key val)
  (cons (list key val)  (delete map key))
  )

(define (delete map key)
  (delete-help map key '())
  )


(define (delete-help map key before)
  (cond
    ((eq? map '()) before)
    ((eq? (first (first map)) key) (append before (rest map)))  ;key to delete found
    (#t (delete-help (rest map) key (cons (first map) before))) ;this is not meant to be deleted
    )
  )