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

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

;;;;;;
;;; Projection

(def class* environment ()
  ((bindings)))

(def (projection e) evaluator ()
  ())

;;;;;;
;;; Construction

(def (function e) make-environment (bindings)
  (make-instance 'environment :bindings bindings))

(def (function e) make-projection/evaluator ()
  (make-projection 'evaluator))

;;;;;;
;;; Construction

(def (macro e) evaluator ()
  '(make-projection/evaluator))

;;;;;;
;;; Printer

(def printer evaluator (projection recursion input input-reference output-reference)
  (declare (ignore projection recursion))
  (bind ((output nil))
    (labels ((evaluate (environment form)
               (etypecase form
                 (hu.dwim.walker:constant-form (hu.dwim.walker:value-of form))
                 (hu.dwim.walker:free-application-form
                  (bind ((operator (hu.dwim.walker:operator-of form))
                         (arguments (iter (for argument :in (hu.dwim.walker:arguments-of form))
                                          (collect (evaluate environment argument)))))
                    (push (hu.dwim.walker:walk-form `(,operator ,@arguments)) output)
                    (apply operator arguments))))))
      (evaluate (make-environment nil) input))
    (make-iomap/object input input-reference (nreverse output) output-reference)))

;;;;;;
;;; Reader

(def reader evaluator (projection recursion input input-reference output-reference)
  (declare (ignore projection recursion input input-reference output-reference))
  nil)