(define (display-to-string val)
  (let ((exp-port (open-output-string)))
    (display val exp-port)
    (get-output-string exp-port)))

;;expression as string
(define (write-to-string val)
  (let ((exp-port (open-output-string)))
    (write val exp-port)
    (get-output-string exp-port)))

(define (on/off-option-processor name)
  (lambda (option arg-name arg ops)
    (cons (cons name #t) ops)))


(define (paste-selection vals marks? for-scheme-mode? to-scheme to-command)
  (if marks?
      (if for-scheme-mode?
          (format #f "'(~a)" (string-join (map to-scheme vals)))
          (string-join (map to-command vals)))
      (if (null? vals)
          ""
          (if for-scheme-mode?
              (to-scheme (car vals))
              (to-command (car vals))))))

(define *redisplay-everything* #t)

(define (set-redisplay-everything)
  (set! *redisplay-everything* #t))

(define (unset-redisplay-everything)
  (set! *redisplay-everything* #f))

(define (redisplay-everything?)
  *redisplay-everything*)