#lang racket/base

(module+ test

  (require yaragg/examples/0n1
           yaragg/support
           rackunit)

  (define (lex ip)
    (port-count-lines! ip)
    (lambda ()
      (define next-char (read-char ip))
      (cond [(eof-object? next-char)
             (token eof)]
            [(char=? next-char #\0)
             (token "0" "0")]
            [(char=? next-char #\1)
             (token "1" "1")])))


  (check-equal? (syntax->datum (parse #f (lex (open-input-string "1"))))
                '(rule "1"))


  (check-equal? (syntax->datum (parse #f (lex (open-input-string "01"))))
                '(rule "0" "1"))


  (check-equal? (syntax->datum (parse #f (lex (open-input-string "001"))))
                '(rule "0" "0" "1"))


  (check-exn exn:fail:parsing?
             (lambda ()
               (parse #f (lex (open-input-string "0")))))

  (check-exn exn:fail:parsing?
             (lambda ()
               (parse #f (lex (open-input-string "10")))))

  (check-exn exn:fail:parsing?
             (lambda ()
               (parse #f (lex (open-input-string "010")))))


  ;; This should fail predictably because we're passing in tokens
  ;; that the parser doesn't know.
  (check-exn exn:fail:parsing? 
             (lambda () (parse '("zero" "one" "zero"))))
  (check-exn (regexp (regexp-quote
                      "Encountered unexpected token of type \"zero\" (value \"zero\") while parsing"))
             (lambda () (parse '("zero" "one" "zero")))))