(load "C:\\pc.scm")

(define <digit-1-9>
  (range #\1 #\9))
(define <digit-0-9>
  (range #\0 #\9))
(define <nat>
  (new (*parser (char #\0))
       (*pack (lambda (_) 0))

       (*parser <digit-1-9>)
       (*parser <digit-0-9>) *star
       (*caten 2)
       (*pack-with
    (lambda (a s)
      (string->number
       (list->string
        `(,a ,@s)))))

       (*disj 2)
       done))

(define <var>
  (new (*parser (char #\~))
    (*parser (char #\{))
    (*caten 2)
    (*parser (char #\ )) *star
    (*parser <any-char>)
    (*parser (char #\ )) *star
    *diff
    (*parser (char #\}))
    (*parser (char #\~))
    (*caten 2)
    *diff
    ))