query.lisp

(defpackage query
  (:use :cl :gen-machine)
  (:import-from :utils :query-p)
  (:export :make-machine :parse :valid :value :leftover))
(in-package query)
(defclass machine (gen-machine) ())
(defun make-machine (chars) (make-instance 'machine :leftover chars))
(defmethod parse ((m machine))
  (consume m)
  (cond ((delta m "question" 'query-p) (move m "query"))
        ((delta m "query" 'query-p) (move m "query"))
        ((delta-final m #\? "empty") (move m "question"))
        ((delta-final m #\# "empty" "query") (move m "final*"))
        ((final m "empty" "query") (move m "final"))
        (t (move m "error")))
  (cond ((string= (state m) "error") nil)
        ((string= (state m) "final") t)
        ((string= (state m) "final*") (unconsume m) t)
        ((string= (state m) "question") (parse m))
        (t (save m) (parse m))))