;;; -*-lisp-*-
;;;
;;; Parser contexts for scanners
;;;
;;; (c) 2009 Straylight/Edgeware
;;;

;;;----- Licensing notice ---------------------------------------------------
;;;
;;; This file is part of the Sensible Object Design, an object system for C.
;;;
;;; SOD is free software; you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 2 of the License, or
;;; (at your option) any later version.
;;;
;;; SOD is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with SOD; if not, write to the Free Software Foundation,
;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

(cl:in-package #:sod-parser)

;;;--------------------------------------------------------------------------
;;; Basic scanner behaviour.

;; Basic scanners.

(defmethod parser-step ((context scanner-context))
  `(scanner-step ,(parser-scanner context)))

(defmethod parser-at-eof-p ((context scanner-context))
  `(scanner-at-eof-p ,(parser-scanner context)))

(defmethod parser-capture-place ((context scanner-context))
  `(scanner-capture-place ,(parser-scanner context)))

(defmethod parser-restore-place ((context scanner-context) place)
  `(scanner-restore-place ,(parser-scanner context) ,place))

(defmethod parser-release-place ((context scanner-context) place)
  `(scanner-release-place ,(parser-scanner context) ,place))

;; Character scanners.

(defmethod parser-current-char ((context character-scanner-context))
  `(scanner-current-char ,(parser-scanner context)))

;; Token scanners.

(defmethod parser-token-type ((context token-scanner-context))
  `(token-type ,(parser-scanner context)))

(defmethod parser-token-value ((context token-scanner-context))
  `(token-value ,(parser-scanner context)))

;;;--------------------------------------------------------------------------
;;; Contexts for specific scanner classes.

;; String scanner.

(defclass string-scanner-context (character-scanner-context)
  ()
  (:documentation
   "Specialized parser context for scanning strings.

   Most notably, string positions don't need to be released, which means that
   the expanded code doesn't need to do install `unwind-protect' handlers."))

(defmethod parser-places-must-be-released-p
    ((context string-scanner-context))
  nil)

;; List scanner.

(defclass list-scanner-context (token-scanner-context)
  ()
  (:documentation
   "Specialized scanner contexts for the list scanner."))

(defmethod parser-places-must-be-released-p ((context list-scanner-context))
  nil)

;;;----- That's all, folks --------------------------------------------------