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6 ;;;; to the software are in the public domain and are provided with
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12 ;;;; Copyright (c) 1985, 1986, 1987, 1988, 1989, 1990 Xerox Corporation.
13 ;;;; All rights reserved.
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16 ;;;; upon this software are permitted. Any distribution of this software or
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20 ;;;; This software is made available AS IS, and Xerox Corporation makes no
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26 (defmacro define-method-combination (&whole form &rest args)
27 (declare (ignore args))
30 (expand-long-defcombin form)
31 (expand-short-defcombin form)))
33 ;;;; standard method combination
35 ;;; The STANDARD method combination type is implemented directly by
36 ;;; the class STANDARD-METHOD-COMBINATION. The method on
37 ;;; COMPUTE-EFFECTIVE-METHOD does standard method combination directly
38 ;;; and is defined by hand in the file combin.lisp. The method for
39 ;;; FIND-METHOD-COMBINATION must appear in this file for bootstrapping
41 (defmethod find-method-combination ((generic-function generic-function)
42 (type (eql 'standard))
45 (method-combination-error
46 "The method combination type STANDARD accepts no options."))
47 *standard-method-combination*)
49 ;;;; short method combinations
51 ;;;; Short method combinations all follow the same rule for computing the
52 ;;;; effective method. So, we just implement that rule once. Each short
53 ;;;; method combination object just reads the parameters out of the object
54 ;;;; and runs the same rule.
56 (defclass short-method-combination (standard-method-combination)
58 :reader short-combination-operator
60 (identity-with-one-argument
61 :reader short-combination-identity-with-one-argument
62 :initarg :identity-with-one-argument))
63 (:predicate-name short-method-combination-p))
65 (defun expand-short-defcombin (whole)
66 (let* ((type (cadr whole))
68 (getf (cddr whole) :documentation ""))
69 (identity-with-one-arg
70 (getf (cddr whole) :identity-with-one-argument nil))
72 (getf (cddr whole) :operator type)))
73 `(load-short-defcombin
74 ',type ',operator ',identity-with-one-arg ',documentation)))
76 (defun load-short-defcombin (type operator ioa doc)
77 (let* ((truename *load-truename*)
79 (list (find-class 'generic-function)
80 (intern-eql-specializer type)
83 (get-method #'find-method-combination () specializers nil))
86 (make-instance 'standard-method
88 :specializers specializers
89 :lambda-list '(generic-function type options)
90 :function (lambda (args nms &rest cm-args)
91 (declare (ignore nms cm-args))
93 (lambda (gf type options)
95 (short-combine-methods
96 type options operator ioa new-method doc))
98 :definition-source `((define-method-combination ,type) ,truename)))
100 (remove-method #'find-method-combination old-method))
101 (add-method #'find-method-combination new-method)))
103 (defun short-combine-methods (type options operator ioa method doc)
104 (cond ((null options) (setq options '(:most-specific-first)))
105 ((equal options '(:most-specific-first)))
106 ((equal options '(:most-specific-last)))
108 (method-combination-error
109 "Illegal options to a short method combination type.~%~
110 The method combination type ~S accepts one option which~%~
111 must be either :MOST-SPECIFIC-FIRST or :MOST-SPECIFIC-LAST."
113 (make-instance 'short-method-combination
117 :identity-with-one-argument ioa
118 :definition-source method
121 (defmethod compute-effective-method ((generic-function generic-function)
122 (combin short-method-combination)
124 (let ((type (method-combination-type combin))
125 (operator (short-combination-operator combin))
126 (ioa (short-combination-identity-with-one-argument combin))
129 (dolist (m applicable-methods)
130 (let ((qualifiers (method-qualifiers m)))
131 (flet ((lose (method why)
132 (invalid-method-error
134 "The method ~S ~A.~%~
135 The method combination type ~S was defined with the~%~
136 short form of DEFINE-METHOD-COMBINATION and so requires~%~
137 all methods have either the single qualifier ~S or the~%~
138 single qualifier :AROUND."
139 method why type type)))
140 (cond ((null qualifiers)
141 (lose m "has no qualifiers"))
143 (lose m "has more than one qualifier"))
144 ((eq (car qualifiers) :around)
146 ((eq (car qualifiers) type)
149 (lose m "has an illegal qualifier"))))))
150 (setq around (nreverse around)
151 primary (nreverse primary))
153 (if (and (null (cdr primary))
155 `(call-method ,(car primary) ())
156 `(,operator ,@(mapcar (lambda (m) `(call-method ,m ()))
158 (cond ((null primary)
159 `(error "No ~S methods for the generic function ~S."
160 ',type ',generic-function))
161 ((null around) main-method)
163 `(call-method ,(car around)
164 (,@(cdr around) (make-method ,main-method))))))))
166 ;;;; long method combinations
168 (defclass long-method-combination (standard-method-combination)
169 ((function :initarg :function
170 :reader long-method-combination-function)))
172 (defun expand-long-defcombin (form)
173 (let ((type (cadr form))
174 (lambda-list (caddr form))
175 (method-group-specifiers (cadddr form))
179 (when (and (consp (car body)) (eq (caar body) :arguments))
180 (setq args-option (cdr (pop body))))
181 (when (and (consp (car body)) (eq (caar body) :generic-function))
182 (setq gf-var (cadr (pop body))))
183 (multiple-value-bind (documentation function)
184 (make-long-method-combination-function
185 type lambda-list method-group-specifiers args-option gf-var
187 `(load-long-defcombin ',type ',documentation #',function))))
189 (defvar *long-method-combination-functions* (make-hash-table :test 'eq))
191 (defun load-long-defcombin (type doc function)
193 (list (find-class 'generic-function)
194 (intern-eql-specializer type)
197 (get-method #'find-method-combination () specializers nil))
199 (make-instance 'standard-method
201 :specializers specializers
202 :lambda-list '(generic-function type options)
203 :function (lambda (args nms &rest cm-args)
204 (declare (ignore nms cm-args))
206 (lambda (generic-function type options)
207 (declare (ignore generic-function options))
208 (make-instance 'long-method-combination
212 :definition-source `((define-method-combination ,type)
214 (setf (gethash type *long-method-combination-functions*) function)
215 (when old-method (remove-method #'find-method-combination old-method))
216 (add-method #'find-method-combination new-method)))
218 (defmethod compute-effective-method ((generic-function generic-function)
219 (combin long-method-combination)
221 (funcall (gethash (method-combination-type combin)
222 *long-method-combination-functions*)
227 (defun make-long-method-combination-function
228 (type ll method-group-specifiers args-option gf-var body)
229 ;;(declare (values documentation function))
230 (declare (ignore type))
231 (multiple-value-bind (documentation declarations real-body)
232 (extract-declarations body)
235 (wrap-method-group-specifier-bindings method-group-specifiers
239 (push `(,gf-var .generic-function.) (cadr wrapped-body)))
242 (setq wrapped-body (deal-with-args-option wrapped-body args-option)))
246 `(apply #'(lambda ,ll ,wrapped-body)
247 (method-combination-options .method-combination.))))
251 `(lambda (.generic-function. .method-combination. .applicable-methods.)
252 (progn .generic-function. .method-combination. .applicable-methods.)
253 (block .long-method-combination-function. ,wrapped-body))))))
255 ;; parse-method-group-specifiers parse the method-group-specifiers
257 (defun wrap-method-group-specifier-bindings
258 (method-group-specifiers declarations real-body)
264 (dolist (method-group-specifier method-group-specifiers)
265 (multiple-value-bind (name tests description order required)
266 (parse-method-group-specifier method-group-specifier)
267 (declare (ignore description))
268 (let ((specializer-cache (gensym)))
270 (push specializer-cache specializer-caches)
272 (if (equal ,specializer-cache .specializers.)
273 (return-from .long-method-combination-function.
274 '(error "More than one method of type ~S ~
275 with the same specializers."
277 (setq ,specializer-cache .specializers.))
278 (push .method. ,name))
281 (push `(when (null ,name)
282 (return-from .long-method-combination-function.
283 '(error "No ~S methods." ',name)))
285 (loop (unless (and (constantp order)
286 (neq order (setq order (eval order))))
288 (push (cond ((eq order :most-specific-first)
289 `(setq ,name (nreverse ,name)))
290 ((eq order :most-specific-last) ())
293 (:most-specific-first
294 (setq ,name (nreverse ,name)))
295 (:most-specific-last))))
297 `(let (,@(nreverse names) ,@(nreverse specializer-caches))
299 (dolist (.method. .applicable-methods.)
300 (let ((.qualifiers. (method-qualifiers .method.))
301 (.specializers. (method-specializers .method.)))
302 (progn .qualifiers. .specializers.)
303 (cond ,@(nreverse cond-clauses))))
304 ,@(nreverse required-checks)
305 ,@(nreverse order-cleanups)
308 (defun parse-method-group-specifier (method-group-specifier)
309 ;;(declare (values name tests description order required))
310 (let* ((name (pop method-group-specifier))
316 (if (or (null method-group-specifier)
317 (memq (car method-group-specifier)
318 '(:description :order :required)))
319 (return-from collect-tests t)
320 (let ((pattern (pop method-group-specifier)))
321 (push pattern patterns)
322 (push (parse-qualifier-pattern name pattern)
324 (nreverse collect))))
327 (getf method-group-specifier :description
328 (make-default-method-group-description patterns))
329 (getf method-group-specifier :order :most-specific-first)
330 (getf method-group-specifier :required nil))))
332 (defun parse-qualifier-pattern (name pattern)
333 (cond ((eq pattern '()) `(null .qualifiers.))
335 ((symbolp pattern) `(,pattern .qualifiers.))
336 ((listp pattern) `(qualifier-check-runtime ',pattern .qualifiers.))
337 (t (error "In the method group specifier ~S,~%~
338 ~S isn't a valid qualifier pattern."
341 (defun qualifier-check-runtime (pattern qualifiers)
342 (loop (cond ((and (null pattern) (null qualifiers))
344 ((eq pattern '*) (return t))
345 ((and pattern qualifiers (eq (car pattern) (car qualifiers)))
350 (defun make-default-method-group-description (patterns)
353 "methods matching one of the patterns: ~{~S, ~} ~S"
354 (butlast patterns) (car (last patterns)))
356 "methods matching the pattern: ~S"
359 ;;; This baby is a complete mess. I can't believe we put it in this
360 ;;; way. No doubt this is a large part of what drives MLY crazy.
362 ;;; At runtime (when the effective-method is run), we bind an intercept
363 ;;; lambda-list to the arguments to the generic function.
365 ;;; At compute-effective-method time, the symbols in the :arguments
366 ;;; option are bound to the symbols in the intercept lambda list.
367 (defun deal-with-args-option (wrapped-body args-option)
368 (let* ((intercept-lambda-list
370 (dolist (arg args-option)
371 (if (memq arg lambda-list-keywords)
373 (push (gensym) collect)))
375 (intercept-rebindings
376 (loop for arg in args-option
377 for int in intercept-lambda-list
378 unless (memq arg lambda-list-keywords)
379 collect `(,arg ',int))))
380 (setf (cadr wrapped-body)
381 (append intercept-rebindings (cadr wrapped-body)))
383 ;; Be sure to fill out the intercept lambda list so that it can
384 ;; be too short if it wants to.
385 (cond ((memq '&rest intercept-lambda-list))
386 ((memq '&allow-other-keys intercept-lambda-list))
387 ((memq '&key intercept-lambda-list)
388 (setq intercept-lambda-list
389 (append intercept-lambda-list '(&allow-other-keys))))
391 (setq intercept-lambda-list
392 (append intercept-lambda-list '(&rest .ignore.)))))
394 `(let ((inner-result. ,wrapped-body))
395 `(apply #'(lambda ,',intercept-lambda-list
396 ,,(when (memq '.ignore. intercept-lambda-list)
397 ''(declare (ignore .ignore.)))
399 .combined-method-args.))))