;;; -*- mode: Lisp; Syntax: Common-Lisp; -*-
;;;
;;; Copyright (c) 2009 by the authors.
;;;
;;; See LICENCE for details.

(in-package :hu.dwim.projectional-editor)

;;;;;;
;;; Sequential projection

(def class* projection/sequential (projection)
  ((elements :type sequence)))

;;;;;;
;;; Projection constructors

(def (function e) make-projection/sequential (elements)
  (make-instance 'projection/sequential :elements elements))

;;;;;;
;;; Sequential printer

(def method project-document (document (projection projection/sequential))
  (iter (for current-document :initially document :then (project-document current-document current-projection))
        (for current-projection :in-sequence (elements-of projection))
        ;; TODO: mapping
        (finally (return current-document))))

;;;;;;
;;; Sequential reader

;; TODO: KLUDGE: what is this? do we really need this?
(def class* xxx ()
  ((document :type document)
   (operation :type operation)))

(def method read-operation (document (projection projection/sequential) xxx)
  (iter (for current-document :initially (project-document document projection) :then (document-of (source-of current-document)))
        (for current-source = (source-of current-document))
        (while current-source)
        (for current-projection = (projection-of current-source))
        (for current-xxx :initially xxx :then (make-instance 'xxx :document current-document :operation (read-operation (document-of current-source) current-projection current-xxx)))
        (finally (return (or (operation-of current-xxx) (call-next-method))))))