;;; This is an example list to play with
(define bar 
  '((created_at)
    (id)
    (id_str)
    ((user)
     (name)
     (screen_name)
     (location))
    (geo)
    ((status)
     (date)
     ((web)
      (url)
      (description))
     (time))
    (coordinates)))

;;; My current version (that doesn't work properly)
(define (foo lst)
  (cond [(null? lst) '()]
	[(list? (car lst))
	 (cons (car (car lst))
	       (foo (cdr (car lst))))]
	[else (cons (car lst)
		    (foo (cdr lst)))]))

;;; This gets things done (well, it should anyway)
(map (lambda (x) (foo x)) bar)

;;; What I want it to return:
'((created_at)
  (id)
  (user name)
  (user screen_name)
  (user location)
  (geo)
  (status date)
  (status web url)
  (status web description)
  (status time)
  (coordinates))

;;; The call to map currently returns. 
'((created_at)
  (id)
  (id_str)
  (user)
  (geo)
  (status)
  (coordinates))

(define (transform lst)
  (define (prefix x)
    (map (lambda (y)
           (if (pair? (car y))
               (cons (append (car x) (car y)) (cdr y))
               (append (car x) y)))
         (cdr x)))

  (reverse!
   (let loop ((lst lst) (result '()))
     (if (null? lst)
         result
         (let ((x (car lst)))
           (if (pair? (car x))
               (loop (append (prefix x) (cdr lst))
                     result)
               (loop (cdr lst)
                     (cons x result))))))))

(define (transform lst)
  (define (prefix x)
    (map (lambda (y)
           (if (pair? (car y))
               (cons (append (car x) (car y)) (cdr y))
               (append (car x) y)))
         (cdr x)))

  (let loop ((lst lst) (result '()))
    (if (null? lst)
        (reverse! result)
        (let ((x (car lst)))
          (if (pair? (car x))
              (loop (append (prefix x) (cdr lst))
                    result)
              (loop (cdr lst)
                    (cons x result)))))))