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 ,@(mapcar (lambda (x)
103 `(declaim (ftype (function (t) t) ,x)))
104 *readers-for-this-defclass*)
105 ,@(mapcar (lambda (x)
106 `(declaim (ftype (function (t t) t) ,x)))
107 *writers-for-this-defclass*)
108 ,@(mapcar (lambda (x)
109 `(declaim (ftype (function (t) t)
110 ,(slot-reader-name x)
111 ,(slot-boundp-name x))
112 (ftype (function (t t) t)
113 ,(slot-writer-name x))))
114 *slot-names-for-this-defclass*)
115 (let ,(mapcar #'cdr *initfunctions-for-this-defclass*)
116 (load-defclass ',name
119 (list ,@canonical-slots)
120 (list ,@(apply #'append
122 '(:from-defclass-p t))
123 other-initargs)))))))
126 ;; FIXME: (YUK!) Why do we do this? Because in order
127 ;; to make the defstruct form, we need to know what
128 ;; the accessors for the slots are, so we need
129 ;; already to have hooked into the CLOS machinery.
131 ;; There may be a better way to do this: it would
132 ;; involve knowing enough about PCL to ask "what
133 ;; will my slot names and accessors be"; failing
134 ;; this, we currently just evaluate the whole
135 ;; kaboodle, and then use CLASS-DIRECT-SLOTS. --
138 (let* ((include (or (and supers
139 (fix-super (car supers)))
140 (and (not (eq name 'structure-object))
141 *the-class-structure-object*)))
142 (defstruct-form (make-structure-class-defstruct-form
143 name (class-direct-slots (find-class name)) include)))
145 (eval-when (:compile-toplevel :load-toplevel :execute)
146 ,defstruct-form) ; really compile the defstruct-form
147 (eval-when (:compile-toplevel :load-toplevel :execute)
150 ;; By telling the type system at compile time about
151 ;; the existence of a class named NAME, we can avoid
152 ;; various bogus warnings about "type isn't defined yet"
153 ;; for code elsewhere in the same file which uses
154 ;; the name of the type.
156 ;; We only need to do this at compile time, because
157 ;; at load and execute time we write the actual
158 ;; full-blown class, so the "a class of this name is
159 ;; coming" note we write here would be irrelevant.
160 (eval-when (:compile-toplevel)
161 (preinform-compiler-about-class-type ',name))
162 ,defclass-form))))))))
164 (defun make-initfunction (initform)
165 (cond ((or (eq initform t)
166 (equal initform ''t))
167 '(function constantly-t))
168 ((or (eq initform nil)
169 (equal initform ''nil))
170 '(function constantly-nil))
171 ((or (eql initform 0)
172 (equal initform ''0))
173 '(function constantly-0))
175 (let ((entry (assoc initform *initfunctions-for-this-defclass*
178 (setq entry (list initform
180 `(function (lambda () ,initform))))
181 (push entry *initfunctions-for-this-defclass*))
184 (defun canonicalize-slot-specification (class-name spec env)
185 (labels ((slot-name-illegal (reason)
186 (error 'simple-program-error
188 (format nil "~~@<in DEFCLASS ~~S, the slot name in the ~
189 specification ~~S is ~A.~~@:>" reason)
190 :format-arguments (list class-name spec)))
191 (check-slot-name-legality (name)
193 ((not (symbolp name))
194 (slot-name-illegal "not a symbol"))
196 (slot-name-illegal "a keyword"))
197 ((constantp name env)
198 (slot-name-illegal "a constant")))))
200 (check-slot-name-legality spec)
201 (push spec *slot-names-for-this-defclass*)
204 (check-slot-name-legality (car spec))
205 (push (car spec) *slot-names-for-this-defclass*)
206 `'(:name ,(car spec)))
208 (error 'simple-program-error
210 "~@<in DEFCLASS ~S, the slot specification ~S is invalid; ~
211 the probable intended meaning may be achieved by ~
212 specifiying ~S instead."
214 (list class-name spec
215 `(,(car spec) :initform ,(cadr spec)))))
217 (let* ((name (car spec))
222 (unsupplied (list nil))
223 (initform (getf spec :initform unsupplied)))
224 (check-slot-name-legality name)
225 (push name *slot-names-for-this-defclass*)
226 (doplist (key val) spec
228 (:accessor (push val readers)
229 (push `(setf ,val) writers))
230 (:reader (push val readers))
231 (:writer (push val writers))
232 (:initarg (push val initargs))))
233 (loop (unless (remf spec :accessor) (return)))
234 (loop (unless (remf spec :reader) (return)))
235 (loop (unless (remf spec :writer) (return)))
236 (loop (unless (remf spec :initarg) (return)))
237 (setq *writers-for-this-defclass*
238 (append writers *writers-for-this-defclass*))
239 (setq *readers-for-this-defclass*
240 (append readers *readers-for-this-defclass*))
241 (setq spec `(:name ',name
246 (if (eq initform unsupplied)
248 `(list* :initfunction ,(make-initfunction initform)
251 (defun canonicalize-defclass-option (class-name option)
252 (declare (ignore class-name))
255 (let ((canonical ()))
256 (let (key val (tail (cdr option)))
257 (loop (when (null tail) (return nil))
260 (push ``(,',key ,,(make-initfunction val) ,',val) canonical))
261 `(:direct-default-initargs (list ,@(nreverse canonical))))))
263 `(',(car option) ',(cadr option)))
265 `(',(car option) ',(cdr option)))))
267 ;;; This is the early definition of LOAD-DEFCLASS. It just collects up
268 ;;; all the class definitions in a list. Later, in braid1.lisp, these
269 ;;; are actually defined.
271 ;;; Each entry in *EARLY-CLASS-DEFINITIONS* is an EARLY-CLASS-DEFINITION.
272 (defparameter *early-class-definitions* ())
274 (defun early-class-definition (class-name)
275 (or (find class-name *early-class-definitions* :key #'ecd-class-name)
276 (error "~S is not a class in *early-class-definitions*." class-name)))
278 (defun make-early-class-definition
279 (name source metaclass
280 superclass-names canonical-slots other-initargs)
281 (list 'early-class-definition
282 name source metaclass
283 superclass-names canonical-slots other-initargs))
285 (defun ecd-class-name (ecd) (nth 1 ecd))
286 (defun ecd-source (ecd) (nth 2 ecd))
287 (defun ecd-metaclass (ecd) (nth 3 ecd))
288 (defun ecd-superclass-names (ecd) (nth 4 ecd))
289 (defun ecd-canonical-slots (ecd) (nth 5 ecd))
290 (defun ecd-other-initargs (ecd) (nth 6 ecd))
292 (defvar *early-class-slots* nil)
294 (defun canonical-slot-name (canonical-slot)
295 (getf canonical-slot :name))
297 (defun early-class-slots (class-name)
298 (cdr (or (assoc class-name *early-class-slots*)
299 (let ((a (cons class-name
300 (mapcar #'canonical-slot-name
301 (early-collect-inheritance class-name)))))
302 (push a *early-class-slots*)
305 (defun early-class-size (class-name)
306 (length (early-class-slots class-name)))
308 (defun early-collect-inheritance (class-name)
309 ;;(declare (values slots cpl default-initargs direct-subclasses))
310 (let ((cpl (early-collect-cpl class-name)))
311 (values (early-collect-slots cpl)
313 (early-collect-default-initargs cpl)
315 (dolist (definition *early-class-definitions*)
316 (when (memq class-name (ecd-superclass-names definition))
317 (push (ecd-class-name definition) collect)))
318 (nreverse collect)))))
320 (defun early-collect-slots (cpl)
321 (let* ((definitions (mapcar #'early-class-definition cpl))
322 (super-slots (mapcar #'ecd-canonical-slots definitions))
323 (slots (apply #'append (reverse super-slots))))
325 (let ((name1 (canonical-slot-name s1)))
326 (dolist (s2 (cdr (memq s1 slots)))
327 (when (eq name1 (canonical-slot-name s2))
328 (error "More than one early class defines a slot with the~%~
329 name ~S. This can't work because the bootstrap~%~
330 object system doesn't know how to compute effective~%~
335 (defun early-collect-cpl (class-name)
337 (let* ((definition (early-class-definition c))
338 (supers (ecd-superclass-names definition)))
340 (apply #'append (mapcar #'early-collect-cpl supers))))))
341 (remove-duplicates (walk class-name) :from-end nil :test #'eq)))
343 (defun early-collect-default-initargs (cpl)
344 (let ((default-initargs ()))
345 (dolist (class-name cpl)
346 (let* ((definition (early-class-definition class-name))
347 (others (ecd-other-initargs definition)))
348 (loop (when (null others) (return nil))
349 (let ((initarg (pop others)))
350 (unless (eq initarg :direct-default-initargs)
351 (error "~@<The defclass option ~S is not supported by ~
352 the bootstrap object system.~:@>"
354 (setq default-initargs
355 (nconc default-initargs (reverse (pop others)))))))
356 (reverse default-initargs)))
358 (defun !bootstrap-slot-index (class-name slot-name)
359 (or (position slot-name (early-class-slots class-name))
360 (error "~S not found" slot-name)))
362 ;;; !BOOTSTRAP-GET-SLOT and !BOOTSTRAP-SET-SLOT are used to access and
363 ;;; change the values of slots during bootstrapping. During
364 ;;; bootstrapping, there are only two kinds of objects whose slots we
365 ;;; need to access, CLASSes and SLOT-DEFINITIONs. The first argument
366 ;;; to these functions tells whether the object is a CLASS or a
369 ;;; Note that the way this works it stores the slot in the same place
370 ;;; in memory that the full object system will expect to find it
371 ;;; later. This is critical to the bootstrapping process, the whole
372 ;;; changeover to the full object system is predicated on this.
374 ;;; One important point is that the layout of standard classes and
375 ;;; standard slots must be computed the same way in this file as it is
376 ;;; by the full object system later.
377 (defmacro !bootstrap-get-slot (type object slot-name)
378 `(clos-slots-ref (get-slots ,object)
379 (!bootstrap-slot-index ,type ,slot-name)))
380 (defun !bootstrap-set-slot (type object slot-name new-value)
381 (setf (!bootstrap-get-slot type object slot-name) new-value))
383 (defun early-class-name (class)
384 (!bootstrap-get-slot 'class class 'name))
386 (defun early-class-precedence-list (class)
387 (!bootstrap-get-slot 'pcl-class class 'class-precedence-list))
389 (defun early-class-name-of (instance)
390 (early-class-name (class-of instance)))
392 (defun early-class-slotds (class)
393 (!bootstrap-get-slot 'slot-class class 'slots))
395 (defun early-slot-definition-name (slotd)
396 (!bootstrap-get-slot 'standard-effective-slot-definition slotd 'name))
398 (defun early-slot-definition-location (slotd)
399 (!bootstrap-get-slot 'standard-effective-slot-definition slotd 'location))
401 (defun early-accessor-method-slot-name (method)
402 (!bootstrap-get-slot 'standard-accessor-method method 'slot-name))
404 (unless (fboundp 'class-name-of)
405 (setf (symbol-function 'class-name-of)
406 (symbol-function 'early-class-name-of)))
407 (unintern 'early-class-name-of)
409 (defun early-class-direct-subclasses (class)
410 (!bootstrap-get-slot 'class class 'direct-subclasses))
412 (declaim (notinline load-defclass))
413 (defun load-defclass (name metaclass supers canonical-slots canonical-options)
414 (setq supers (copy-tree supers)
415 canonical-slots (copy-tree canonical-slots)
416 canonical-options (copy-tree canonical-options))
418 (make-early-class-definition name
425 (find name *early-class-definitions* :key #'ecd-class-name)))
426 (setq *early-class-definitions*
427 (cons ecd (remove existing *early-class-definitions*)))