erkin

#lang racket/base
(require racket/gui/base
         racket/class
         racket/list
         racket/string)

(define program-name "regexp-checker")
(define program-version "v0.1")

(define version-message

erkin

#lang racket

(module amb racket/base
  (provide amb assert!)
  (define-syntax-rule (pop! stack)
    (begin0 (car stack) (set! stack (cdr stack))))
  (define-syntax-rule (push! v stack)
    (set! stack (cons v stack)))
  (define (U f) (f f))

erkin

(define-syntax define-syntax-rule
  (syntax-rules ()
    ((_ (name args ...) body)
     (define-syntax name
       (syntax-rules ()
         ((name args ...) body))))))

(define-syntax-rule (do-times n . body)
  (do ((i n (sub1 i)))
      ((< i 1))

erkin

(define (read-csexp)
 (letrec
     ((left-paren  (char->integer #\())
      (right-paren (char->integer #\)))
      (zero        (char->integer #\0))
      (nine        (char->integer #\9))
      (colon       (char->integer #\:))
      (in (current-input-port))
      (read-atom
       (λ (byte digits)