gsi v4.9.3 owner@localhost:~/sync/Scripts/Lambda$ gsi ./automaton.scm *** ERROR IN "automaton.scm"@21.30 -- Ill-formed selector list

automaton.scm

;#!/usr/bin/env scheme-r5rs
;https://github.com/carld/automata-via-macros
(define-syntax automaton ;https://cs.brown.edu/~sk/Publications/Talks/SwineBeforePerl/
  (syntax-rules (:)
    [(_ init-state
         (state : response ...) ...)
     (let-syntax
          ([process-state
            (syntax-rules (accept ->)
              [(_ accept)
               (lambda (stream)
                  (cond
                   [(null? stream) #t]
                   [else #f]))]
              [(_ (label -> target) (... ...))
              (lambda (stream)
                  (cond
                   [(null? stream) #f]
                   [else (case (car stream)
                            [(label) (target (cdr stream))]
                            (... ...)
                            [else #f])]))])])
          (letrec ([state (process-state response ...)] ...)
            init-state))]))

(define m2
  (automaton init
    [init : (c -> more)]
    [more : (a -> more)
            (d -> more)
            (r -> end)]
    [end : accept]))

(define-syntax test
  (syntax-rules()
    ((_ expression expectation)
       (cond
          ((equal? expression expectation)
               (display "TEST OK" )(newline))
          (else  (error "Unexpected result " expression))))))

(test  (m2 `(c a d r))  #t)
(test  (m2 `(c d a a d r))  #t)
(test  (m2 `(r))  #f)
(test  (m2 `(i))  #f)
(test  (m2 `(a))  #f)
(test  (m2 `(c))  #f)
(test  (m2 `(c a r))  #t)