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 (defclass 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 attribute)
  54           (make-instance 'standard-attribute
  55                          :name name
  56                          'effective-attribute attribute
  57                          'description-class class))
  58     attribute))
  59
  60
  61 (defclass standard-description-class (description-access-class layered-class)
  62   ()
  63   (:default-initargs :defining-metaclass 'description-access-class))
  64
  65 (defmethod validate-superclass
  66            ((class standard-description-class)
  67             (superclass standard-class))
  68   t)
  69
  70 (defclass standard-description-object (standard-layer-object) ())
  71
  72 (defun description-class-name  (description-class)
  73     (read-from-string (symbol-name (class-name description-class))))
  74
  75 (defun initialize-description-class (class)
  76
  77   ;;; HACK: initialization does not happen properly
  78   ;;; when compiling and loading or something like that.
  79   ;;; Obviously i'm not sure why.
  80   ;;; So we're going to explicitly initialize things.
  81   ;;; For now. --drewc
  82
  83   (pushnew class *defined-descriptions*)
  84
  85   ;;; ENDHACK.
  86
  87   (let* ((description (find-layer class))
  88          (attribute-objects (mapcar #'attribute-object (class-slots (class-of description))))
  89          (defining-classes (partial-class-defining-classes (class-of description))))
  90
  91
  92
  93     (loop
  94        :for (layer class)
  95        :on  defining-classes :by #'cddr
  96        :do (funcall-with-layer-context
  97             (adjoin-layer (find-layer layer) (current-layer-context))
  98            (lambda ()
  99              (loop :for direct-slot :in (class-direct-slots class)
 100                 :do (let ((attribute
 101                            (find (slot-definition-name direct-slot)
 102                                  attribute-objects
 103                                  :key #'attribute-name)))
 104                       (apply #'reinitialize-instance attribute
 105                              (direct-attribute-properties direct-slot))
 106                       (apply #'change-class attribute (attribute-class attribute) (direct-attribute-properties direct-slot))
 107
 108                       (setf (slot-value description (attribute-name attribute))
 109                             attribute))))))))
 110
 111 ;;;; HACK: run this at startup till we figure things out.
 112 (defun initialize-descriptions ()
 113   (map nil #'initialize-description-class
 114        (setf *defined-descriptions*
 115              (remove-duplicates *defined-descriptions*))))
 116
 117 (defmethod initialize-instance :around ((class standard-description-class) &rest initargs &key (direct-superclasses '()))
 118   (declare (dynamic-extent initargs))
 119   (prog1
 120       (if (loop for direct-superclass in direct-superclasses
 121                 thereis (ignore-errors (subtypep direct-superclass 'standard-description-object)))
 122         (call-next-method)
 123         (apply #'call-next-method
 124                class
 125                :direct-superclasses
 126                (append direct-superclasses
 127                        (list (find-class 'standard-description-object)))
 128                initargs))
 129     (initialize-description-class class)))
 130
 131
 132 (defmethod reinitialize-instance :around ((class standard-description-class) &rest initargs &key (direct-superclasses '() direct-superclasses-p))
 133   (declare (dynamic-extent initargs))
 134 ;  (warn "CLASS ~A ARGS ~A:" class initargs)
 135   (prog1
 136       (if (or (not direct-superclasses-p)
 137                 (loop for direct-superclass in direct-superclasses
 138                       thereis (ignore-errors (subtypep direct-superclass 'standard-description-object))))
 139           (call-next-method)
 140           (apply #'call-next-method
 141                  class
 142                  :direct-superclasses
 143                  (append direct-superclasses
 144                          (list (find-class 'standard-description-object)))
 145                  initargs))
 146     (initialize-description-class class)))
 147
 148
 149 (defmethod print-object ((object standard-description-object) stream)
 150   (print-unreadable-object (object stream :type nil :identity t)
 151     (format stream "DESCRIPTION ~A" (ignore-errors (description-print-name object)))))
 152
 153 (defmethod print-object ((object standard-description-class) stream)
 154   (print-unreadable-object (object stream :type t :identity t)
 155     (princ  (ignore-errors (description-print-name (find-layer object))) stream)))
 156
 157 (defun find-description (name)
 158   (find-layer (find-class (defining-description name))))
 159
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