src/description-class.lisp

   1 (in-package :lisp-on-lines)
   2
   3 ;;;; * DESCRIPTIONS
   4 ;;;; A description is an object which is used
   5 ;;;; to describe another object.
   6
   7 ;;; HACK:
   8 ;;; Since i'm not using deflayer, ensure-layer etc,
   9 ;;; There are a few places where contextl gets confused
  10 ;;; trying to locate my description layers.
  11
  12 ;;; TODO: investigate switching to deflayer!
  13
  14 (defun contextl::prepare-layer (layer)
  15   (if (symbolp layer)
  16       (if (eq (symbol-package layer)
  17           (find-package :description-definers))
  18           layer
  19           (contextl::defining-layer layer))
  20
  21       layer))
  22
  23 (defmethod find-layer-class :around ((layer symbol) &optional errorp environment)
  24   (if (eq (symbol-package layer)
  25           (find-package :description-definers))
  26       (find-class layer)
  27       (call-next-method)))
  28
  29 ;;; #+HACK
  30 ;;; I'm having some 'issues' with
  31 ;;; compiled code and my initialization.
  32 ;;; So this hack initializes the world.
  33 (eval-when (:compile-toplevel :load-toplevel :execute)
  34   (defparameter *defined-descriptions* nil))
  35
  36 (define-layered-class description-access-class (standard-layer-class contextl::special-layered-access-class )
  37   ((defined-in-descriptions :initarg :in-description)
  38    (mixin-class-p :initarg :mixinp)))
  39
  40 (defmethod direct-slot-definition-class
  41            ((class description-access-class) &key &allow-other-keys)
  42   (find-class 'direct-attribute-definition-class))
  43
  44 (defmethod effective-slot-definition-class
  45            ((class description-access-class) &key &allow-other-keys)
  46   (find-class 'effective-attribute-definition-class))
  47
  48 (defmethod compute-effective-slot-definition
  49            ((class description-access-class) name direct-slot-definitions)
  50   (declare (ignore name))
  51   (let ((attribute (call-next-method)))
  52     (setf (attribute-direct-attributes attribute) direct-slot-definitions)
  53     (setf (attribute-object-initargs attribute)
  54           ;; This plist will be used to init the attribute object
  55           ;; Once the description itself is properly initiated.
  56           (list :name name
  57                 'effective-attribute attribute
  58                 'description-class class))
  59     attribute))
  60
  61
  62 (defclass standard-description-class (description-access-class layered-class)
  63   ()
  64   (:default-initargs :defining-metaclass 'description-access-class))
  65
  66 (defmethod validate-superclass
  67            ((class standard-description-class)
  68             (superclass standard-class))
  69   t)
  70
  71 (defclass standard-description-object (standard-layer-object)
  72   ())
  73
  74 (defun description-class-name  (description-class)
  75     (read-from-string (symbol-name (class-name description-class))))
  76
  77 (defun initialize-description-class (class)
  78
  79 ;;; HACK: initialization does not happ   en properly
  80 ;;; when compiling and loading or something like that.
  81 ;;; Obviously i'm not sure why.
  82 ;;; So we're going to explicitly initialize things.
  83 ;;; For now. --drewc
  84
  85   (pushnew class *defined-descriptions*)
  86
  87 ;;; ENDHACK.
  88
  89   (let* ((description (find-layer class))
  90          (attribute-objects
  91           (mapcar
  92            (lambda (slot)
  93              (setf (attribute-object slot)
  94                    (apply #'make-instance
  95                           'standard-attribute
  96                           (attribute-object-initargs slot))))
  97            (class-slots (class-of description))))
  98          (defining-classes (partial-class-defining-classes (class-of description))))
  99
 100     (loop
 101        :for (layer class)
 102        :on  defining-classes :by #'cddr
 103        :do (funcall-with-layer-context
 104             (adjoin-layer (find-layer layer) (current-layer-context))
 105             (lambda ()
 106               (loop :for direct-slot :in (class-direct-slots class)
 107                  :do (let ((attribute
 108                             (find (slot-definition-name direct-slot)
 109                                   attribute-objects
 110                                   :key #'attribute-name)))
 111                        (let ((initargs
 112                               (prepare-initargs attribute (direct-attribute-properties direct-slot))))
 113
 114                          (apply #'reinitialize-instance attribute
 115                                 initargs )
 116                          (when (not (eq (find-class (attribute-class attribute))
 117                                         (class-of attribute)))
 118
 119                            (apply #'change-class attribute  (attribute-class attribute)
 120                                   initargs)))
 121
 122
 123                        (setf (slot-value description (attribute-name attribute))
 124                              attribute))))))))
 125
 126 ;;;; HACK: run this at startup till we figure things out.
 127 (defun initialize-descriptions ()
 128   (map nil #'initialize-description-class
 129        (setf *defined-descriptions*
 130              (remove-duplicates *defined-descriptions*))))
 131
 132 (defmethod initialize-instance :around ((class standard-description-class) &rest initargs &key (direct-superclasses '()))
 133   (declare (dynamic-extent initargs))
 134   (prog1
 135       (if (loop for direct-superclass in direct-superclasses
 136                 thereis (ignore-errors (subtypep direct-superclass 'standard-description-object)))
 137         (call-next-method)
 138         (apply #'call-next-method
 139                class
 140                :direct-superclasses
 141                (append direct-superclasses
 142                        (list (find-class 'standard-description-object)))
 143                initargs))
 144     (initialize-description-class class)))
 145
 146
 147 (defmethod reinitialize-instance :around ((class standard-description-class) &rest initargs &key (direct-superclasses '() direct-superclasses-p))
 148   (declare (dynamic-extent initargs))
 149 ;  (warn "CLASS ~A ARGS ~A:" class initargs)
 150   (prog1
 151       (if (or (not direct-superclasses-p)
 152                 (loop for direct-superclass in direct-superclasses
 153                       thereis (ignore-errors (subtypep direct-superclass 'standard-description-object))))
 154           (call-next-method)
 155           (apply #'call-next-method
 156                  class
 157                  :direct-superclasses
 158                  (append direct-superclasses
 159                          (list (find-class 'standard-description-object)))
 160                  initargs))
 161     (initialize-description-class class)))
 162
 163
 164 (defmethod print-object ((object standard-description-object) stream)
 165   (print-unreadable-object (object stream :type nil :identity t)
 166     (format stream "DESCRIPTION ~A" (ignore-errors (description-print-name object)))))
 167
 168 (defmethod print-object ((object standard-description-class) stream)
 169   (print-unreadable-object (object stream :type t :identity t)
 170     (princ  (ignore-errors (description-print-name (find-layer object))) stream)))
 171
 172 (defun find-description (name)
 173   (find-layer (find-class (defining-description name))))
 174
 175
 176
 177
 178
 179