1 ;;;; This software is part of the SBCL system. See the README file for
4 ;;;; This software is derived from software originally released by Xerox
5 ;;;; Corporation. Copyright and release statements follow. Later modifications
6 ;;;; to the software are in the public domain and are provided with
7 ;;;; absolutely no warranty. See the COPYING and CREDITS files for more
10 ;;;; copyright information from original PCL sources:
12 ;;;; Copyright (c) 1985, 1986, 1987, 1988, 1989, 1990 Xerox Corporation.
13 ;;;; All rights reserved.
15 ;;;; Use and copying of this software and preparation of derivative works based
16 ;;;; upon this software are permitted. Any distribution of this software or
17 ;;;; derivative works must comply with all applicable United States export
20 ;;;; This software is made available AS IS, and Xerox Corporation makes no
21 ;;;; warranty about the software, its performance or its conformity to any
26 ;;;; DEFCLASS macro and close personal friends
28 ;;; ANSI says (Macro DEFCLASS, section 7.7) that DEFCLASS, if it
29 ;;; "appears as a top level form, the compiler must make the class
30 ;;; name be recognized as a valid type name in subsequent declarations
31 ;;; (as for deftype) and be recognized as a valid class name for
32 ;;; defmethod parameter specializers and for use as the :metaclass
33 ;;; option of a subsequent defclass."
34 (defun preinform-compiler-about-class-type (name)
35 ;; Unless the type system already has an actual type attached to
36 ;; NAME (in which case (1) writing a placeholder value over that
37 ;; actual type as a compile-time side-effect would probably be a bad
38 ;; idea and (2) anyway we don't need to modify it in order to make
39 ;; NAME be recognized as a valid type name)
40 (unless (info :type :kind name)
41 ;; Tell the compiler to expect a class with the given NAME, by
42 ;; writing a kind of minimal placeholder type information. This
43 ;; placeholder will be overwritten later when the class is defined.
44 (setf (info :type :kind name) :forthcoming-defclass-type))
47 ;;; state for the current DEFCLASS expansion
48 (defvar *initfunctions-for-this-defclass*)
49 (defvar *readers-for-this-defclass*)
50 (defvar *writers-for-this-defclass*)
52 ;;; Like the DEFMETHOD macro, the expansion of the DEFCLASS macro is
53 ;;; fixed. DEFCLASS always expands into a call to LOAD-DEFCLASS. Until
54 ;;; the meta-braid is set up, LOAD-DEFCLASS has a special definition
55 ;;; which simply collects all class definitions up, when the metabraid
56 ;;; is initialized it is done from those class definitions.
58 ;;; After the metabraid has been setup, and the protocol for defining
59 ;;; classes has been defined, the real definition of LOAD-DEFCLASS is
60 ;;; installed by the file std-class.lisp
61 (defmacro defclass (name %direct-superclasses %direct-slots &rest %options)
62 (let ((supers (copy-tree %direct-superclasses))
63 (slots (copy-tree %direct-slots))
64 (options (copy-tree %options)))
65 (let ((metaclass 'standard-class))
66 (dolist (option options)
67 (if (not (listp option))
68 (error "~S is not a legal defclass option." option)
69 (when (eq (car option) :metaclass)
70 (unless (legal-class-name-p (cadr option))
71 (error "The value of the :metaclass option (~S) is not a~%~
76 (cl:standard-class 'standard-class)
77 (cl:structure-class 'structure-class)
79 (setf options (remove option options))
82 (let ((*initfunctions-for-this-defclass* ())
83 (*readers-for-this-defclass* ()) ;Truly a crock, but we got
84 (*writers-for-this-defclass* ())) ;to have it to live nicely.
85 (let ((canonical-slots
86 (mapcar (lambda (spec)
87 (canonicalize-slot-specification name spec))
90 (mapcar (lambda (option)
91 (canonicalize-defclass-option name option))
93 ;; DEFSTRUCT-P should be true if the class is defined
94 ;; with a metaclass STRUCTURE-CLASS, so that a DEFSTRUCT
95 ;; is compiled for the class.
96 (defstruct-p (and (eq *boot-state* 'complete)
97 (let ((mclass (find-class metaclass nil)))
101 *the-class-structure-class*))))))
104 ,@(mapcar (lambda (x)
105 `(declaim (ftype (function (t) t) ,x)))
106 *readers-for-this-defclass*)
107 ,@(mapcar (lambda (x)
108 `(declaim (ftype (function (t t) t) ,x)))
109 *writers-for-this-defclass*)
110 (let ,(mapcar #'cdr *initfunctions-for-this-defclass*)
111 (load-defclass ',name
114 (list ,@canonical-slots)
115 (list ,@(apply #'append
117 '(:from-defclass-p t))
118 other-initargs)))))))
121 ;; FIXME: (YUK!) Why do we do this? Because in order
122 ;; to make the defstruct form, we need to know what
123 ;; the accessors for the slots are, so we need
124 ;; already to have hooked into the CLOS machinery.
126 ;; There may be a better way to do this: it would
127 ;; involve knowing enough about PCL to ask "what
128 ;; will my slot names and accessors be"; failing
129 ;; this, we currently just evaluate the whole
130 ;; kaboodle, and then use CLASS-DIRECT-SLOTS. --
133 (let* ((include (or (and supers
134 (fix-super (car supers)))
135 (and (not (eq name 'structure-object))
136 *the-class-structure-object*)))
137 (defstruct-form (make-structure-class-defstruct-form
138 name (class-direct-slots (find-class name)) include)))
140 (eval-when (:compile-toplevel :load-toplevel :execute)
141 ,defstruct-form) ; really compile the defstruct-form
142 (eval-when (:compile-toplevel :load-toplevel :execute)
145 ;; By telling the type system at compile time about
146 ;; the existence of a class named NAME, we can avoid
147 ;; various bogus warnings about "type isn't defined yet"
148 ;; for code elsewhere in the same file which uses
149 ;; the name of the type.
151 ;; We only need to do this at compile time, because
152 ;; at load and execute time we write the actual
153 ;; full-blown class, so the "a class of this name is
154 ;; coming" note we write here would be irrelevant.
155 (eval-when (:compile-toplevel)
156 (preinform-compiler-about-class-type ',name))
157 ,defclass-form))))))))
159 (defun make-initfunction (initform)
160 (cond ((or (eq initform t)
161 (equal initform ''t))
162 '(function constantly-t))
163 ((or (eq initform nil)
164 (equal initform ''nil))
165 '(function constantly-nil))
166 ((or (eql initform 0)
167 (equal initform ''0))
168 '(function constantly-0))
170 (let ((entry (assoc initform *initfunctions-for-this-defclass*
173 (setq entry (list initform
175 `(function (lambda () ,initform))))
176 (push entry *initfunctions-for-this-defclass*))
179 (defun canonicalize-slot-specification (class-name spec)
180 (cond ((and (symbolp spec)
181 (not (keywordp spec))
182 (not (memq spec '(t nil))))
185 (error "~S is not a legal slot specification." spec))
187 `'(:name ,(car spec)))
189 (error "In DEFCLASS ~S, the slot specification ~S is obsolete.~%~
191 class-name spec (list (car spec) :initform (cadr spec))))
193 (let* ((name (pop spec))
197 (unsupplied (list nil))
198 (initform (getf spec :initform unsupplied)))
199 (doplist (key val) spec
201 (:accessor (push val readers)
202 (push `(setf ,val) writers))
203 (:reader (push val readers))
204 (:writer (push val writers))
205 (:initarg (push val initargs))))
206 (loop (unless (remf spec :accessor) (return)))
207 (loop (unless (remf spec :reader) (return)))
208 (loop (unless (remf spec :writer) (return)))
209 (loop (unless (remf spec :initarg) (return)))
210 (setq *writers-for-this-defclass*
211 (append writers *writers-for-this-defclass*))
212 (setq *readers-for-this-defclass*
213 (append readers *readers-for-this-defclass*))
214 (setq spec `(:name ',name
219 (if (eq initform unsupplied)
221 `(list* :initfunction ,(make-initfunction initform) ,@spec))))))
223 (defun canonicalize-defclass-option (class-name option)
224 (declare (ignore class-name))
227 (let ((canonical ()))
228 (let (key val (tail (cdr option)))
229 (loop (when (null tail) (return nil))
232 (push ``(,',key ,,(make-initfunction val) ,',val) canonical))
233 `(:direct-default-initargs (list ,@(nreverse canonical))))))
235 `(',(car option) ',(cadr option)))
237 `(',(car option) ',(cdr option)))))
239 ;;; This is the early definition of LOAD-DEFCLASS. It just collects up
240 ;;; all the class definitions in a list. Later, in braid1.lisp, these
241 ;;; are actually defined.
243 ;;; Each entry in *EARLY-CLASS-DEFINITIONS* is an EARLY-CLASS-DEFINITION.
244 (defparameter *early-class-definitions* ())
246 (defun early-class-definition (class-name)
247 (or (find class-name *early-class-definitions* :key #'ecd-class-name)
248 (error "~S is not a class in *early-class-definitions*." class-name)))
250 (defun make-early-class-definition
251 (name source metaclass
252 superclass-names canonical-slots other-initargs)
253 (list 'early-class-definition
254 name source metaclass
255 superclass-names canonical-slots other-initargs))
257 (defun ecd-class-name (ecd) (nth 1 ecd))
258 (defun ecd-source (ecd) (nth 2 ecd))
259 (defun ecd-metaclass (ecd) (nth 3 ecd))
260 (defun ecd-superclass-names (ecd) (nth 4 ecd))
261 (defun ecd-canonical-slots (ecd) (nth 5 ecd))
262 (defun ecd-other-initargs (ecd) (nth 6 ecd))
264 (defvar *early-class-slots* nil)
266 (defun canonical-slot-name (canonical-slot)
267 (getf canonical-slot :name))
269 (defun early-class-slots (class-name)
270 (cdr (or (assoc class-name *early-class-slots*)
271 (let ((a (cons class-name
272 (mapcar #'canonical-slot-name
273 (early-collect-inheritance class-name)))))
274 (push a *early-class-slots*)
277 (defun early-class-size (class-name)
278 (length (early-class-slots class-name)))
280 (defun early-collect-inheritance (class-name)
281 ;;(declare (values slots cpl default-initargs direct-subclasses))
282 (let ((cpl (early-collect-cpl class-name)))
283 (values (early-collect-slots cpl)
285 (early-collect-default-initargs cpl)
287 (dolist (definition *early-class-definitions*)
288 (when (memq class-name (ecd-superclass-names definition))
289 (push (ecd-class-name definition) collect)))
290 (nreverse collect)))))
292 (defun early-collect-slots (cpl)
293 (let* ((definitions (mapcar #'early-class-definition cpl))
294 (super-slots (mapcar #'ecd-canonical-slots definitions))
295 (slots (apply #'append (reverse super-slots))))
297 (let ((name1 (canonical-slot-name s1)))
298 (dolist (s2 (cdr (memq s1 slots)))
299 (when (eq name1 (canonical-slot-name s2))
300 (error "More than one early class defines a slot with the~%~
301 name ~S. This can't work because the bootstrap~%~
302 object system doesn't know how to compute effective~%~
307 (defun early-collect-cpl (class-name)
309 (let* ((definition (early-class-definition c))
310 (supers (ecd-superclass-names definition)))
312 (apply #'append (mapcar #'early-collect-cpl supers))))))
313 (remove-duplicates (walk class-name) :from-end nil :test #'eq)))
315 (defun early-collect-default-initargs (cpl)
316 (let ((default-initargs ()))
317 (dolist (class-name cpl)
318 (let* ((definition (early-class-definition class-name))
319 (others (ecd-other-initargs definition)))
320 (loop (when (null others) (return nil))
321 (let ((initarg (pop others)))
322 (unless (eq initarg :direct-default-initargs)
323 (error "~@<The defclass option ~S is not supported by ~
324 the bootstrap object system.~:@>"
326 (setq default-initargs
327 (nconc default-initargs (reverse (pop others)))))))
328 (reverse default-initargs)))
330 (defun !bootstrap-slot-index (class-name slot-name)
331 (or (position slot-name (early-class-slots class-name))
332 (error "~S not found" slot-name)))
334 ;;; !BOOTSTRAP-GET-SLOT and !BOOTSTRAP-SET-SLOT are used to access and
335 ;;; change the values of slots during bootstrapping. During
336 ;;; bootstrapping, there are only two kinds of objects whose slots we
337 ;;; need to access, CLASSes and SLOT-DEFINITIONs. The first argument
338 ;;; to these functions tells whether the object is a CLASS or a
341 ;;; Note that the way this works it stores the slot in the same place
342 ;;; in memory that the full object system will expect to find it
343 ;;; later. This is critical to the bootstrapping process, the whole
344 ;;; changeover to the full object system is predicated on this.
346 ;;; One important point is that the layout of standard classes and
347 ;;; standard slots must be computed the same way in this file as it is
348 ;;; by the full object system later.
349 (defmacro !bootstrap-get-slot (type object slot-name)
350 `(clos-slots-ref (get-slots ,object)
351 (!bootstrap-slot-index ,type ,slot-name)))
352 (defun !bootstrap-set-slot (type object slot-name new-value)
353 (setf (!bootstrap-get-slot type object slot-name) new-value))
355 (defun early-class-name (class)
356 (!bootstrap-get-slot 'class class 'name))
358 (defun early-class-precedence-list (class)
359 (!bootstrap-get-slot 'pcl-class class 'class-precedence-list))
361 (defun early-class-name-of (instance)
362 (early-class-name (class-of instance)))
364 (defun early-class-slotds (class)
365 (!bootstrap-get-slot 'slot-class class 'slots))
367 (defun early-slot-definition-name (slotd)
368 (!bootstrap-get-slot 'standard-effective-slot-definition slotd 'name))
370 (defun early-slot-definition-location (slotd)
371 (!bootstrap-get-slot 'standard-effective-slot-definition slotd 'location))
373 (defun early-accessor-method-slot-name (method)
374 (!bootstrap-get-slot 'standard-accessor-method method 'slot-name))
376 (unless (fboundp 'class-name-of)
377 (setf (symbol-function 'class-name-of)
378 (symbol-function 'early-class-name-of)))
379 (unintern 'early-class-name-of)
381 (defun early-class-direct-subclasses (class)
382 (!bootstrap-get-slot 'class class 'direct-subclasses))
384 (declaim (notinline load-defclass))
385 (defun load-defclass (name metaclass supers canonical-slots canonical-options)
386 (setq supers (copy-tree supers)
387 canonical-slots (copy-tree canonical-slots)
388 canonical-options (copy-tree canonical-options))
390 (make-early-class-definition name
397 (find name *early-class-definitions* :key #'ecd-class-name)))
398 (setq *early-class-definitions*
399 (cons ecd (remove existing *early-class-definitions*)))