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 (defun preinform-compiler-about-accessors (readers writers slots)
48 (flet ((inform (name type)
49 ;; FIXME: This matches what PROCLAIM FTYPE does, except
50 ;; that :WHERE-FROM is :DEFINED, not :DECLARED, and should
51 ;; probably be factored into a common function -- eg.
52 ;; (%proclaim-ftype name declared-or-defined).
53 (when (eq (info :function :where-from name) :assumed)
54 (proclaim-as-fun-name name)
55 (note-name-defined name :function)
56 (setf (info :function :where-from name) :defined
57 (info :function :type name) type))))
58 (let ((rtype (specifier-type '(function (t) t)))
59 (wtype (specifier-type '(function (t t) t))))
60 (dolist (reader readers)
61 (inform reader rtype))
62 (dolist (writer writers)
63 (inform writer wtype))
65 (inform (slot-reader-name slot) rtype)
66 (inform (slot-boundp-name slot) rtype)
67 (inform (slot-writer-name slot) wtype)))))
69 ;;; state for the current DEFCLASS expansion
70 (defvar *initfunctions-for-this-defclass*)
71 (defvar *readers-for-this-defclass*)
72 (defvar *writers-for-this-defclass*)
73 (defvar *slot-names-for-this-defclass*)
75 ;;; Like the DEFMETHOD macro, the expansion of the DEFCLASS macro is
76 ;;; fixed. DEFCLASS always expands into a call to LOAD-DEFCLASS. Until
77 ;;; the meta-braid is set up, LOAD-DEFCLASS has a special definition
78 ;;; which simply collects all class definitions up, when the metabraid
79 ;;; is initialized it is done from those class definitions.
81 ;;; After the metabraid has been setup, and the protocol for defining
82 ;;; classes has been defined, the real definition of LOAD-DEFCLASS is
83 ;;; installed by the file std-class.lisp
84 (defmacro defclass (&environment env name %direct-superclasses %direct-slots &rest %options)
85 (let ((supers (copy-tree %direct-superclasses))
86 (slots (copy-tree %direct-slots))
87 (options (copy-tree %options)))
88 (let ((metaclass 'standard-class))
89 (dolist (option options)
90 (if (not (listp option))
91 (error "~S is not a legal defclass option." option)
92 (when (eq (car option) :metaclass)
93 (unless (legal-class-name-p (cadr option))
94 (error "The value of the :metaclass option (~S) is not a~%~
97 (setq metaclass (cadr option))
98 (setf options (remove option options))
101 (let ((*initfunctions-for-this-defclass* ())
102 (*readers-for-this-defclass* ()) ;Truly a crock, but we got
103 (*writers-for-this-defclass* ()) ;to have it to live nicely.
104 (*slot-names-for-this-defclass* ()))
105 (let ((canonical-slots
106 (mapcar (lambda (spec)
107 (canonicalize-slot-specification name spec env))
110 (mapcar (lambda (option)
111 (canonicalize-defclass-option name option))
113 ;; DEFSTRUCT-P should be true if the class is defined
114 ;; with a metaclass STRUCTURE-CLASS, so that a DEFSTRUCT
115 ;; is compiled for the class.
116 (defstruct-p (and (eq *boot-state* 'complete)
117 (let ((mclass (find-class metaclass nil)))
121 *the-class-structure-class*))))))
122 (let* ((defclass-form
123 `(let ,(mapcar #'cdr *initfunctions-for-this-defclass*)
124 (load-defclass ',name
127 (list ,@canonical-slots)
128 (list ,@(apply #'append
130 '(:from-defclass-p t))
132 ',*readers-for-this-defclass*
133 ',*writers-for-this-defclass*
134 ',*slot-names-for-this-defclass*))))
137 ;; FIXME: (YUK!) Why do we do this? Because in order
138 ;; to make the defstruct form, we need to know what
139 ;; the accessors for the slots are, so we need
140 ;; already to have hooked into the CLOS machinery.
142 ;; There may be a better way to do this: it would
143 ;; involve knowing enough about PCL to ask "what
144 ;; will my slot names and accessors be"; failing
145 ;; this, we currently just evaluate the whole
146 ;; kaboodle, and then use CLASS-DIRECT-SLOTS. --
149 (let* ((include (or (and supers
150 (fix-super (car supers)))
151 (and (not (eq name 'structure-object))
152 *the-class-structure-object*)))
153 (defstruct-form (make-structure-class-defstruct-form
154 name (class-direct-slots (find-class name))
157 (eval-when (:compile-toplevel :load-toplevel :execute)
158 ,defstruct-form) ; really compile the defstruct-form
159 (eval-when (:compile-toplevel :load-toplevel :execute)
162 ;; By telling the type system at compile time about
163 ;; the existence of a class named NAME, we can avoid
164 ;; various bogus warnings about "type isn't defined yet"
165 ;; for code elsewhere in the same file which uses
166 ;; the name of the type.
168 ;; We only need to do this at compile time, because
169 ;; at load and execute time we write the actual
170 ;; full-blown class, so the "a class of this name is
171 ;; coming" note we write here would be irrelevant.
172 (eval-when (:compile-toplevel)
173 (%compiler-defclass ',name
174 ',*readers-for-this-defclass*
175 ',*writers-for-this-defclass*
176 ',*slot-names-for-this-defclass*))
177 (eval-when (:load-toplevel :execute)
178 ,defclass-form)))))))))
180 (defun %compiler-defclass (name readers writers slots)
181 (preinform-compiler-about-class-type name)
182 (preinform-compiler-about-accessors readers writers slots))
184 (defun make-initfunction (initform)
185 (cond ((or (eq initform t)
186 (equal initform ''t))
187 '(function constantly-t))
188 ((or (eq initform nil)
189 (equal initform ''nil))
190 '(function constantly-nil))
191 ((or (eql initform 0)
192 (equal initform ''0))
193 '(function constantly-0))
195 (let ((entry (assoc initform *initfunctions-for-this-defclass*
198 (setq entry (list initform
200 `(function (lambda () ,initform))))
201 (push entry *initfunctions-for-this-defclass*))
204 (defun canonicalize-slot-specification (class-name spec env)
205 (labels ((slot-name-illegal (reason)
206 (error 'simple-program-error
208 (format nil "~~@<in DEFCLASS ~~S, the slot name in the ~
209 specification ~~S is ~A.~~@:>" reason)
210 :format-arguments (list class-name spec)))
211 (check-slot-name-legality (name)
213 ((not (symbolp name))
214 (slot-name-illegal "not a symbol"))
216 (slot-name-illegal "a keyword"))
217 ((constantp name env)
218 (slot-name-illegal "a constant")))))
220 (check-slot-name-legality spec)
221 (push spec *slot-names-for-this-defclass*)
224 (check-slot-name-legality (car spec))
225 (push (car spec) *slot-names-for-this-defclass*)
226 `'(:name ,(car spec)))
228 (error 'simple-program-error
230 "~@<in DEFCLASS ~S, the slot specification ~S is invalid; ~
231 the probable intended meaning may be achieved by ~
232 specifiying ~S instead.~>"
234 (list class-name spec
235 `(,(car spec) :initform ,(cadr spec)))))
237 (let* ((name (car spec))
242 (unsupplied (list nil))
243 (initform (getf spec :initform unsupplied)))
244 (check-slot-name-legality name)
245 (push name *slot-names-for-this-defclass*)
246 (doplist (key val) spec
248 (:accessor (push val readers)
249 (push `(setf ,val) writers))
250 (:reader (push val readers))
251 (:writer (push val writers))
252 (:initarg (push val initargs))))
253 (loop (unless (remf spec :accessor) (return)))
254 (loop (unless (remf spec :reader) (return)))
255 (loop (unless (remf spec :writer) (return)))
256 (loop (unless (remf spec :initarg) (return)))
257 (setq *writers-for-this-defclass*
258 (append writers *writers-for-this-defclass*))
259 (setq *readers-for-this-defclass*
260 (append readers *readers-for-this-defclass*))
261 (setq spec `(:name ',name
266 (if (eq initform unsupplied)
268 `(list* :initfunction ,(make-initfunction initform)
271 (defun canonicalize-defclass-option (class-name option)
272 (declare (ignore class-name))
275 (let ((canonical ()))
276 (let (key val (tail (cdr option)))
277 (loop (when (null tail) (return nil))
280 (push ``(,',key ,,(make-initfunction val) ,',val) canonical))
281 `(:direct-default-initargs (list ,@(nreverse canonical))))))
283 `(',(car option) ',(cadr option)))
285 `(',(car option) ',(cdr option)))))
287 ;;; This is the early definition of LOAD-DEFCLASS. It just collects up
288 ;;; all the class definitions in a list. Later, in braid1.lisp, these
289 ;;; are actually defined.
291 ;;; Each entry in *EARLY-CLASS-DEFINITIONS* is an EARLY-CLASS-DEFINITION.
292 (defparameter *early-class-definitions* ())
294 (defun early-class-definition (class-name)
295 (or (find class-name *early-class-definitions* :key #'ecd-class-name)
296 (error "~S is not a class in *early-class-definitions*." class-name)))
298 (defun make-early-class-definition
299 (name source metaclass
300 superclass-names canonical-slots other-initargs)
301 (list 'early-class-definition
302 name source metaclass
303 superclass-names canonical-slots other-initargs))
305 (defun ecd-class-name (ecd) (nth 1 ecd))
306 (defun ecd-source (ecd) (nth 2 ecd))
307 (defun ecd-metaclass (ecd) (nth 3 ecd))
308 (defun ecd-superclass-names (ecd) (nth 4 ecd))
309 (defun ecd-canonical-slots (ecd) (nth 5 ecd))
310 (defun ecd-other-initargs (ecd) (nth 6 ecd))
312 (defvar *early-class-slots* nil)
314 (defun canonical-slot-name (canonical-slot)
315 (getf canonical-slot :name))
317 (defun early-class-slots (class-name)
318 (cdr (or (assoc class-name *early-class-slots*)
319 (let ((a (cons class-name
320 (mapcar #'canonical-slot-name
321 (early-collect-inheritance class-name)))))
322 (push a *early-class-slots*)
325 (defun early-class-size (class-name)
326 (length (early-class-slots class-name)))
328 (defun early-collect-inheritance (class-name)
329 ;;(declare (values slots cpl default-initargs direct-subclasses))
330 (let ((cpl (early-collect-cpl class-name)))
331 (values (early-collect-slots cpl)
333 (early-collect-default-initargs cpl)
335 (dolist (definition *early-class-definitions*)
336 (when (memq class-name (ecd-superclass-names definition))
337 (push (ecd-class-name definition) collect)))
338 (nreverse collect)))))
340 (defun early-collect-slots (cpl)
341 (let* ((definitions (mapcar #'early-class-definition cpl))
342 (super-slots (mapcar #'ecd-canonical-slots definitions))
343 (slots (apply #'append (reverse super-slots))))
345 (let ((name1 (canonical-slot-name s1)))
346 (dolist (s2 (cdr (memq s1 slots)))
347 (when (eq name1 (canonical-slot-name s2))
348 (error "More than one early class defines a slot with the~%~
349 name ~S. This can't work because the bootstrap~%~
350 object system doesn't know how to compute effective~%~
355 (defun early-collect-cpl (class-name)
357 (let* ((definition (early-class-definition c))
358 (supers (ecd-superclass-names definition)))
360 (apply #'append (mapcar #'early-collect-cpl supers))))))
361 (remove-duplicates (walk class-name) :from-end nil :test #'eq)))
363 (defun early-collect-default-initargs (cpl)
364 (let ((default-initargs ()))
365 (dolist (class-name cpl)
366 (let* ((definition (early-class-definition class-name))
367 (others (ecd-other-initargs definition)))
368 (loop (when (null others) (return nil))
369 (let ((initarg (pop others)))
370 (unless (eq initarg :direct-default-initargs)
371 (error "~@<The defclass option ~S is not supported by ~
372 the bootstrap object system.~:@>"
374 (setq default-initargs
375 (nconc default-initargs (reverse (pop others)))))))
376 (reverse default-initargs)))
378 (defun !bootstrap-slot-index (class-name slot-name)
379 (or (position slot-name (early-class-slots class-name))
380 (error "~S not found" slot-name)))
382 ;;; !BOOTSTRAP-GET-SLOT and !BOOTSTRAP-SET-SLOT are used to access and
383 ;;; change the values of slots during bootstrapping. During
384 ;;; bootstrapping, there are only two kinds of objects whose slots we
385 ;;; need to access, CLASSes and SLOT-DEFINITIONs. The first argument
386 ;;; to these functions tells whether the object is a CLASS or a
389 ;;; Note that the way this works it stores the slot in the same place
390 ;;; in memory that the full object system will expect to find it
391 ;;; later. This is critical to the bootstrapping process, the whole
392 ;;; changeover to the full object system is predicated on this.
394 ;;; One important point is that the layout of standard classes and
395 ;;; standard slots must be computed the same way in this file as it is
396 ;;; by the full object system later.
397 (defmacro !bootstrap-get-slot (type object slot-name)
398 `(clos-slots-ref (get-slots ,object)
399 (!bootstrap-slot-index ,type ,slot-name)))
400 (defun !bootstrap-set-slot (type object slot-name new-value)
401 (setf (!bootstrap-get-slot type object slot-name) new-value))
403 (defun early-class-name (class)
404 (!bootstrap-get-slot 'class class 'name))
406 (defun early-class-precedence-list (class)
407 (!bootstrap-get-slot 'pcl-class class 'class-precedence-list))
409 (defun early-class-name-of (instance)
410 (early-class-name (class-of instance)))
412 (defun early-class-slotds (class)
413 (!bootstrap-get-slot 'slot-class class 'slots))
415 (defun early-slot-definition-name (slotd)
416 (!bootstrap-get-slot 'standard-effective-slot-definition slotd 'name))
418 (defun early-slot-definition-location (slotd)
419 (!bootstrap-get-slot 'standard-effective-slot-definition slotd 'location))
421 (defun early-accessor-method-slot-name (method)
422 (!bootstrap-get-slot 'standard-accessor-method method 'slot-name))
424 (unless (fboundp 'class-name-of)
425 (setf (symbol-function 'class-name-of)
426 (symbol-function 'early-class-name-of)))
427 (unintern 'early-class-name-of)
429 (defun early-class-direct-subclasses (class)
430 (!bootstrap-get-slot 'class class 'direct-subclasses))
432 (declaim (notinline load-defclass))
433 (defun load-defclass (name metaclass supers canonical-slots canonical-options
434 readers writers slot-names)
435 (%compiler-defclass name readers writers slot-names)
436 (preinform-compiler-about-accessors readers writers slot-names)
437 (setq supers (copy-tree supers)
438 canonical-slots (copy-tree canonical-slots)
439 canonical-options (copy-tree canonical-options))
441 (make-early-class-definition name
448 (find name *early-class-definitions* :key #'ecd-class-name)))
449 (setq *early-class-definitions*
450 (cons ecd (remove existing *early-class-definitions*)))