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*)
51 (defvar *slot-names-for-this-defclass*)
53 ;;; Like the DEFMETHOD macro, the expansion of the DEFCLASS macro is
54 ;;; fixed. DEFCLASS always expands into a call to LOAD-DEFCLASS. Until
55 ;;; the meta-braid is set up, LOAD-DEFCLASS has a special definition
56 ;;; which simply collects all class definitions up, when the metabraid
57 ;;; is initialized it is done from those class definitions.
59 ;;; After the metabraid has been setup, and the protocol for defining
60 ;;; classes has been defined, the real definition of LOAD-DEFCLASS is
61 ;;; installed by the file std-class.lisp
62 (defmacro defclass (&environment env name %direct-superclasses %direct-slots &rest %options)
63 (let ((supers (copy-tree %direct-superclasses))
64 (slots (copy-tree %direct-slots))
65 (options (copy-tree %options)))
66 (let ((metaclass 'standard-class))
67 (dolist (option options)
68 (if (not (listp option))
69 (error "~S is not a legal defclass option." option)
70 (when (eq (car option) :metaclass)
71 (unless (legal-class-name-p (cadr option))
72 (error "The value of the :metaclass option (~S) is not a~%~
75 (setq metaclass (cadr option))
76 (setf options (remove option options))
79 (let ((*initfunctions-for-this-defclass* ())
80 (*readers-for-this-defclass* ()) ;Truly a crock, but we got
81 (*writers-for-this-defclass* ()) ;to have it to live nicely.
82 (*slot-names-for-this-defclass* ()))
83 (let ((canonical-slots
84 (mapcar (lambda (spec)
85 (canonicalize-slot-specification name spec env))
88 (mapcar (lambda (option)
89 (canonicalize-defclass-option name option))
91 ;; DEFSTRUCT-P should be true if the class is defined
92 ;; with a metaclass STRUCTURE-CLASS, so that a DEFSTRUCT
93 ;; is compiled for the class.
94 (defstruct-p (and (eq *boot-state* 'complete)
95 (let ((mclass (find-class metaclass nil)))
99 *the-class-structure-class*))))))
102 (let ,(mapcar #'cdr *initfunctions-for-this-defclass*)
103 (%compiler-defclass ',name
104 ',*readers-for-this-defclass*
105 ',*writers-for-this-defclass*
106 ',*slot-names-for-this-defclass*)
107 (load-defclass ',name
110 (list ,@canonical-slots)
111 (list ,@(apply #'append
113 '(:from-defclass-p t))
114 other-initargs)))))))
117 ;; FIXME: (YUK!) Why do we do this? Because in order
118 ;; to make the defstruct form, we need to know what
119 ;; the accessors for the slots are, so we need
120 ;; already to have hooked into the CLOS machinery.
122 ;; There may be a better way to do this: it would
123 ;; involve knowing enough about PCL to ask "what
124 ;; will my slot names and accessors be"; failing
125 ;; this, we currently just evaluate the whole
126 ;; kaboodle, and then use CLASS-DIRECT-SLOTS. --
129 (let* ((include (or (and supers
130 (fix-super (car supers)))
131 (and (not (eq name 'structure-object))
132 *the-class-structure-object*)))
133 (defstruct-form (make-structure-class-defstruct-form
134 name (class-direct-slots (find-class name))
137 (eval-when (:compile-toplevel :load-toplevel :execute)
138 ,defstruct-form) ; really compile the defstruct-form
139 (eval-when (:compile-toplevel :load-toplevel :execute)
142 ;; By telling the type system at compile time about
143 ;; the existence of a class named NAME, we can avoid
144 ;; various bogus warnings about "type isn't defined yet"
145 ;; for code elsewhere in the same file which uses
146 ;; the name of the type.
148 ;; We only need to do this at compile time, because
149 ;; at load and execute time we write the actual
150 ;; full-blown class, so the "a class of this name is
151 ;; coming" note we write here would be irrelevant.
152 (eval-when (:compile-toplevel)
153 (%compiler-defclass ',name
154 ',*readers-for-this-defclass*
155 ',*writers-for-this-defclass*
156 ',*slot-names-for-this-defclass*))
157 (eval-when (:load-toplevel :execute)
158 ,defclass-form)))))))))
160 (defun %compiler-defclass (name readers writers slot-names)
161 (with-single-package-locked-error (:symbol name "defining ~A as a class")
162 (preinform-compiler-about-class-type name)
163 (proclaim `(ftype (function (t) t)
165 ,@(mapcar #'slot-reader-name slot-names)
166 ,@(mapcar #'slot-boundp-name slot-names)))
167 (proclaim `(ftype (function (t t) t)
168 ,@writers ,@(mapcar #'slot-writer-name slot-names)))))
170 (defun make-initfunction (initform)
171 (cond ((or (eq initform t)
172 (equal initform ''t))
173 '(function constantly-t))
174 ((or (eq initform nil)
175 (equal initform ''nil))
176 '(function constantly-nil))
177 ((or (eql initform 0)
178 (equal initform ''0))
179 '(function constantly-0))
181 (let ((entry (assoc initform *initfunctions-for-this-defclass*
184 (setq entry (list initform
186 `(function (lambda () ,initform))))
187 (push entry *initfunctions-for-this-defclass*))
190 (defun canonicalize-slot-specification (class-name spec env)
191 (labels ((slot-name-illegal (reason)
192 (error 'simple-program-error
194 (format nil "~~@<in DEFCLASS ~~S, the slot name in the ~
195 specification ~~S is ~A.~~@:>" reason)
196 :format-arguments (list class-name spec)))
197 (check-slot-name-legality (name)
199 ((not (symbolp name))
200 (slot-name-illegal "not a symbol"))
202 (slot-name-illegal "a keyword"))
203 ((constantp name env)
204 (slot-name-illegal "a constant")))))
206 (check-slot-name-legality spec)
207 (push spec *slot-names-for-this-defclass*)
210 (check-slot-name-legality (car spec))
211 (push (car spec) *slot-names-for-this-defclass*)
212 `'(:name ,(car spec)))
214 (error 'simple-program-error
216 "~@<in DEFCLASS ~S, the slot specification ~S is invalid; ~
217 the probable intended meaning may be achieved by ~
218 specifiying ~S instead.~>"
220 (list class-name spec
221 `(,(car spec) :initform ,(cadr spec)))))
223 (let* ((name (car spec))
228 (unsupplied (list nil))
229 (initform (getf spec :initform unsupplied)))
230 (check-slot-name-legality name)
231 (push name *slot-names-for-this-defclass*)
232 (doplist (key val) spec
234 (:accessor (push val readers)
235 (push `(setf ,val) writers))
236 (:reader (push val readers))
237 (:writer (push val writers))
238 (:initarg (push val initargs))))
239 (loop (unless (remf spec :accessor) (return)))
240 (loop (unless (remf spec :reader) (return)))
241 (loop (unless (remf spec :writer) (return)))
242 (loop (unless (remf spec :initarg) (return)))
243 (setq *writers-for-this-defclass*
244 (append writers *writers-for-this-defclass*))
245 (setq *readers-for-this-defclass*
246 (append readers *readers-for-this-defclass*))
247 (setq spec `(:name ',name
252 (if (eq initform unsupplied)
254 `(list* :initfunction ,(make-initfunction initform)
257 (defun canonicalize-defclass-option (class-name option)
258 (declare (ignore class-name))
261 (let ((canonical ()))
262 (let (key val (tail (cdr option)))
263 (loop (when (null tail) (return nil))
266 (push ``(,',key ,,(make-initfunction val) ,',val) canonical))
267 `(:direct-default-initargs (list ,@(nreverse canonical))))))
269 `(',(car option) ',(cadr option)))
271 `(',(car option) ',(cdr option)))))
273 ;;; This is the early definition of LOAD-DEFCLASS. It just collects up
274 ;;; all the class definitions in a list. Later, in braid1.lisp, these
275 ;;; are actually defined.
277 ;;; Each entry in *EARLY-CLASS-DEFINITIONS* is an EARLY-CLASS-DEFINITION.
278 (defparameter *early-class-definitions* ())
280 (defun early-class-definition (class-name)
281 (or (find class-name *early-class-definitions* :key #'ecd-class-name)
282 (error "~S is not a class in *early-class-definitions*." class-name)))
284 (defun make-early-class-definition
285 (name source metaclass
286 superclass-names canonical-slots other-initargs)
287 (list 'early-class-definition
288 name source metaclass
289 superclass-names canonical-slots other-initargs))
291 (defun ecd-class-name (ecd) (nth 1 ecd))
292 (defun ecd-source (ecd) (nth 2 ecd))
293 (defun ecd-metaclass (ecd) (nth 3 ecd))
294 (defun ecd-superclass-names (ecd) (nth 4 ecd))
295 (defun ecd-canonical-slots (ecd) (nth 5 ecd))
296 (defun ecd-other-initargs (ecd) (nth 6 ecd))
298 (defvar *early-class-slots* nil)
300 (defun canonical-slot-name (canonical-slot)
301 (getf canonical-slot :name))
303 (defun early-class-slots (class-name)
304 (cdr (or (assoc class-name *early-class-slots*)
305 (let ((a (cons class-name
306 (mapcar #'canonical-slot-name
307 (early-collect-inheritance class-name)))))
308 (push a *early-class-slots*)
311 (defun early-class-size (class-name)
312 (length (early-class-slots class-name)))
314 (defun early-collect-inheritance (class-name)
315 ;;(declare (values slots cpl default-initargs direct-subclasses))
316 (let ((cpl (early-collect-cpl class-name)))
317 (values (early-collect-slots cpl)
319 (early-collect-default-initargs cpl)
321 (dolist (definition *early-class-definitions*)
322 (when (memq class-name (ecd-superclass-names definition))
323 (push (ecd-class-name definition) collect)))
324 (nreverse collect)))))
326 (defun early-collect-slots (cpl)
327 (let* ((definitions (mapcar #'early-class-definition cpl))
328 (super-slots (mapcar #'ecd-canonical-slots definitions))
329 (slots (apply #'append (reverse super-slots))))
331 (let ((name1 (canonical-slot-name s1)))
332 (dolist (s2 (cdr (memq s1 slots)))
333 (when (eq name1 (canonical-slot-name s2))
334 (error "More than one early class defines a slot with the~%~
335 name ~S. This can't work because the bootstrap~%~
336 object system doesn't know how to compute effective~%~
341 (defun early-collect-cpl (class-name)
343 (let* ((definition (early-class-definition c))
344 (supers (ecd-superclass-names definition)))
346 (apply #'append (mapcar #'early-collect-cpl supers))))))
347 (remove-duplicates (walk class-name) :from-end nil :test #'eq)))
349 (defun early-collect-default-initargs (cpl)
350 (let ((default-initargs ()))
351 (dolist (class-name cpl)
352 (let* ((definition (early-class-definition class-name))
353 (others (ecd-other-initargs definition)))
354 (loop (when (null others) (return nil))
355 (let ((initarg (pop others)))
356 (unless (eq initarg :direct-default-initargs)
357 (error "~@<The defclass option ~S is not supported by ~
358 the bootstrap object system.~:@>"
360 (setq default-initargs
361 (nconc default-initargs (reverse (pop others)))))))
362 (reverse default-initargs)))
364 (defun !bootstrap-slot-index (class-name slot-name)
365 (or (position slot-name (early-class-slots class-name))
366 (error "~S not found" slot-name)))
368 ;;; !BOOTSTRAP-GET-SLOT and !BOOTSTRAP-SET-SLOT are used to access and
369 ;;; change the values of slots during bootstrapping. During
370 ;;; bootstrapping, there are only two kinds of objects whose slots we
371 ;;; need to access, CLASSes and SLOT-DEFINITIONs. The first argument
372 ;;; to these functions tells whether the object is a CLASS or a
375 ;;; Note that the way this works it stores the slot in the same place
376 ;;; in memory that the full object system will expect to find it
377 ;;; later. This is critical to the bootstrapping process, the whole
378 ;;; changeover to the full object system is predicated on this.
380 ;;; One important point is that the layout of standard classes and
381 ;;; standard slots must be computed the same way in this file as it is
382 ;;; by the full object system later.
383 (defmacro !bootstrap-get-slot (type object slot-name)
384 `(clos-slots-ref (get-slots ,object)
385 (!bootstrap-slot-index ,type ,slot-name)))
386 (defun !bootstrap-set-slot (type object slot-name new-value)
387 (setf (!bootstrap-get-slot type object slot-name) new-value))
389 (defun early-class-name (class)
390 (!bootstrap-get-slot 'class class 'name))
392 (defun early-class-precedence-list (class)
393 (!bootstrap-get-slot 'pcl-class class 'class-precedence-list))
395 (defun early-class-name-of (instance)
396 (early-class-name (class-of instance)))
398 (defun early-class-slotds (class)
399 (!bootstrap-get-slot 'slot-class class 'slots))
401 (defun early-slot-definition-name (slotd)
402 (!bootstrap-get-slot 'standard-effective-slot-definition slotd 'name))
404 (defun early-slot-definition-location (slotd)
405 (!bootstrap-get-slot 'standard-effective-slot-definition slotd 'location))
407 (defun early-accessor-method-slot-name (method)
408 (!bootstrap-get-slot 'standard-accessor-method method 'slot-name))
410 (unless (fboundp 'class-name-of)
411 (setf (symbol-function 'class-name-of)
412 (symbol-function 'early-class-name-of)))
413 (unintern 'early-class-name-of)
415 (defun early-class-direct-subclasses (class)
416 (!bootstrap-get-slot 'class class 'direct-subclasses))
418 (declaim (notinline load-defclass))
419 (defun load-defclass (name metaclass supers canonical-slots canonical-options)
420 (setq supers (copy-tree supers)
421 canonical-slots (copy-tree canonical-slots)
422 canonical-options (copy-tree canonical-options))
424 (make-early-class-definition name
431 (find name *early-class-definitions* :key #'ecd-class-name)))
432 (setq *early-class-definitions*
433 (cons ecd (remove existing *early-class-definitions*)))