read.rkt

(define (parser x phase counter code pointer memory stack)
  (case phase
    ((read-file) (let ((i (read)))
                   (let ((file-name (if (string? i)
                                        i
                                        (symbol->string i))))
                     (let-values (((code stack) (read-file file-name)))
                       (values x phase counter code pointer memory stack)))))
    ((read-char) (values (read-char) phase counter code pointer memory stack))
    ((read) (values (read) phase counter code pointer memory stack))
    (else (values x phase counter code pointer memory stack))))