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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 the class
36 ;;; STANDARD-METHOD-COMBINATION. The method on COMPUTE-EFFECTIVE-METHOD does
37 ;;; standard method combination directly and is defined by hand in the file
38 ;;; combin.lisp. The method for FIND-METHOD-COMBINATION must appear in this
39 ;;; file for bootstrapping reasons.
41 ;;; A commented out copy of this definition appears in combin.lisp.
42 ;;; If you change this definition here, be sure to change it there
44 (defmethod find-method-combination ((generic-function generic-function)
45 (type (eql 'standard))
48 (method-combination-error
49 "The method combination type STANDARD accepts no options."))
50 *standard-method-combination*)
52 ;;;; short method combinations
54 ;;;; Short method combinations all follow the same rule for computing the
55 ;;;; effective method. So, we just implement that rule once. Each short
56 ;;;; method combination object just reads the parameters out of the object
57 ;;;; and runs the same rule.
59 (defclass short-method-combination (standard-method-combination)
61 :reader short-combination-operator
63 (identity-with-one-argument
64 :reader short-combination-identity-with-one-argument
65 :initarg :identity-with-one-argument))
66 (:predicate-name short-method-combination-p))
68 (defun expand-short-defcombin (whole)
69 (let* ((type (cadr whole))
71 (getf (cddr whole) :documentation ""))
72 (identity-with-one-arg
73 (getf (cddr whole) :identity-with-one-argument nil))
75 (getf (cddr whole) :operator type)))
76 (make-top-level-form `(define-method-combination ,type)
77 '(:load-toplevel :execute)
78 `(load-short-defcombin
79 ',type ',operator ',identity-with-one-arg ',documentation))))
81 (defun load-short-defcombin (type operator ioa doc)
82 (let* ((truename *load-truename*)
84 (list (find-class 'generic-function)
85 (intern-eql-specializer type)
88 (get-method #'find-method-combination () specializers nil))
91 (make-instance 'standard-method
93 :specializers specializers
94 :lambda-list '(generic-function type options)
95 :function #'(lambda(args nms &rest cm-args)
96 (declare (ignore nms cm-args))
98 #'(lambda (gf type options)
100 (do-short-method-combination
101 type options operator ioa new-method doc))
103 :definition-source `((define-method-combination ,type) ,truename)))
105 (remove-method #'find-method-combination old-method))
106 (add-method #'find-method-combination new-method)))
108 (defun do-short-method-combination (type options operator ioa method doc)
109 (cond ((null options) (setq options '(:most-specific-first)))
110 ((equal options '(:most-specific-first)))
111 ((equal options '(:most-specific-last)))
113 (method-combination-error
114 "Illegal options to a short method combination type.~%~
115 The method combination type ~S accepts one option which~%~
116 must be either :MOST-SPECIFIC-FIRST or :MOST-SPECIFIC-LAST."
118 (make-instance 'short-method-combination
122 :identity-with-one-argument ioa
123 :definition-source method
126 (defmethod compute-effective-method ((generic-function generic-function)
127 (combin short-method-combination)
129 (let ((type (method-combination-type combin))
130 (operator (short-combination-operator combin))
131 (ioa (short-combination-identity-with-one-argument combin))
134 (dolist (m applicable-methods)
135 (let ((qualifiers (method-qualifiers m)))
136 (flet ((lose (method why)
137 (invalid-method-error
139 "The method ~S ~A.~%~
140 The method combination type ~S was defined with the~%~
141 short form of DEFINE-METHOD-COMBINATION and so requires~%~
142 all methods have either the single qualifier ~S or the~%~
143 single qualifier :AROUND."
144 method why type type)))
145 (cond ((null qualifiers)
146 (lose m "has no qualifiers"))
148 (lose m "has more than one qualifier"))
149 ((eq (car qualifiers) :around)
151 ((eq (car qualifiers) type)
154 (lose m "has an illegal qualifier"))))))
155 (setq around (nreverse around)
156 primary (nreverse primary))
158 (if (and (null (cdr primary))
160 `(call-method ,(car primary) ())
161 `(,operator ,@(mapcar #'(lambda (m) `(call-method ,m ()))
163 (cond ((null primary)
164 `(error "No ~S methods for the generic function ~S."
165 ',type ',generic-function))
166 ((null around) main-method)
168 `(call-method ,(car around)
169 (,@(cdr around) (make-method ,main-method))))))))
171 ;;;; long method combinations
173 (defclass long-method-combination (standard-method-combination)
174 ((function :initarg :function
175 :reader long-method-combination-function)))
177 (defun expand-long-defcombin (form)
178 (let ((type (cadr form))
179 (lambda-list (caddr form))
180 (method-group-specifiers (cadddr form))
182 (arguments-option ())
184 (when (and (consp (car body)) (eq (caar body) :arguments))
185 (setq arguments-option (cdr (pop body))))
186 (when (and (consp (car body)) (eq (caar body) :generic-function))
187 (setq gf-var (cadr (pop body))))
188 (multiple-value-bind (documentation function)
189 (make-long-method-combination-function
190 type lambda-list method-group-specifiers arguments-option gf-var
192 (make-top-level-form `(define-method-combination ,type)
193 '(:load-toplevel :execute)
194 `(load-long-defcombin ',type ',documentation #',function)))))
196 (defvar *long-method-combination-functions* (make-hash-table :test 'eq))
198 (defun load-long-defcombin (type doc function)
200 (list (find-class 'generic-function)
201 (intern-eql-specializer type)
204 (get-method #'find-method-combination () specializers nil))
206 (make-instance 'standard-method
208 :specializers specializers
209 :lambda-list '(generic-function type options)
210 :function #'(lambda (args nms &rest cm-args)
211 (declare (ignore nms cm-args))
213 #'(lambda (generic-function type options)
214 (declare (ignore generic-function options))
215 (make-instance 'long-method-combination
219 :definition-source `((define-method-combination ,type)
221 (setf (gethash type *long-method-combination-functions*) function)
222 (when old-method (remove-method #'find-method-combination old-method))
223 (add-method #'find-method-combination new-method)))
225 (defmethod compute-effective-method ((generic-function generic-function)
226 (combin long-method-combination)
228 (funcall (gethash (method-combination-type combin)
229 *long-method-combination-functions*)
234 (defun make-long-method-combination-function
235 (type ll method-group-specifiers arguments-option gf-var body)
236 ;;(declare (values documentation function))
237 (declare (ignore type))
238 (multiple-value-bind (documentation declarations real-body)
239 (extract-declarations body)
242 (wrap-method-group-specifier-bindings method-group-specifiers
246 (push `(,gf-var .generic-function.) (cadr wrapped-body)))
248 (when arguments-option
249 (setq wrapped-body (deal-with-arguments-option wrapped-body
254 `(apply #'(lambda ,ll ,wrapped-body)
255 (method-combination-options .method-combination.))))
259 `(lambda (.generic-function. .method-combination. .applicable-methods.)
260 (progn .generic-function. .method-combination. .applicable-methods.)
261 (block .long-method-combination-function. ,wrapped-body))))))
263 ;; parse-method-group-specifiers parse the method-group-specifiers
265 (defun wrap-method-group-specifier-bindings
266 (method-group-specifiers declarations real-body)
267 (with-gathering ((names (collecting))
268 (specializer-caches (collecting))
269 (cond-clauses (collecting))
270 (required-checks (collecting))
271 (order-cleanups (collecting)))
272 (dolist (method-group-specifier method-group-specifiers)
273 (multiple-value-bind (name tests description order required)
274 (parse-method-group-specifier method-group-specifier)
275 (declare (ignore description))
276 (let ((specializer-cache (gensym)))
278 (gather specializer-cache specializer-caches)
279 (gather `((or ,@tests)
280 (if (equal ,specializer-cache .specializers.)
281 (return-from .long-method-combination-function.
282 '(error "More than one method of type ~S ~
283 with the same specializers."
285 (setq ,specializer-cache .specializers.))
286 (push .method. ,name))
289 (gather `(when (null ,name)
290 (return-from .long-method-combination-function.
291 '(error "No ~S methods." ',name)))
293 (loop (unless (and (constantp order)
294 (neq order (setq order (eval order))))
296 (gather (cond ((eq order :most-specific-first)
297 `(setq ,name (nreverse ,name)))
298 ((eq order :most-specific-last) ())
301 (:most-specific-first
302 (setq ,name (nreverse ,name)))
303 (:most-specific-last))))
305 `(let (,@names ,@specializer-caches)
307 (dolist (.method. .applicable-methods.)
308 (let ((.qualifiers. (method-qualifiers .method.))
309 (.specializers. (method-specializers .method.)))
310 (progn .qualifiers. .specializers.)
311 (cond ,@cond-clauses)))
316 (defun parse-method-group-specifier (method-group-specifier)
317 ;;(declare (values name tests description order required))
318 (let* ((name (pop method-group-specifier))
321 (gathering1 (collecting)
324 (if (or (null method-group-specifier)
325 (memq (car method-group-specifier)
326 '(:description :order :required)))
327 (return-from collect-tests t)
328 (let ((pattern (pop method-group-specifier)))
329 (push pattern patterns)
330 (gather1 (parse-qualifier-pattern name pattern)))))))))
333 (getf method-group-specifier :description
334 (make-default-method-group-description patterns))
335 (getf method-group-specifier :order :most-specific-first)
336 (getf method-group-specifier :required nil))))
338 (defun parse-qualifier-pattern (name pattern)
339 (cond ((eq pattern '()) `(null .qualifiers.))
341 ((symbolp pattern) `(,pattern .qualifiers.))
342 ((listp pattern) `(qualifier-check-runtime ',pattern .qualifiers.))
343 (t (error "In the method group specifier ~S,~%~
344 ~S isn't a valid qualifier pattern."
347 (defun qualifier-check-runtime (pattern qualifiers)
348 (loop (cond ((and (null pattern) (null qualifiers))
350 ((eq pattern '*) (return t))
351 ((and pattern qualifiers (eq (car pattern) (car qualifiers)))
356 (defun make-default-method-group-description (patterns)
359 "methods matching one of the patterns: ~{~S, ~} ~S"
360 (butlast patterns) (car (last patterns)))
362 "methods matching the pattern: ~S"
365 ;;; This baby is a complete mess. I can't believe we put it in this
366 ;;; way. No doubt this is a large part of what drives MLY crazy.
368 ;;; At runtime (when the effective-method is run), we bind an intercept
369 ;;; lambda-list to the arguments to the generic function.
371 ;;; At compute-effective-method time, the symbols in the :arguments
372 ;;; option are bound to the symbols in the intercept lambda list.
373 (defun deal-with-arguments-option (wrapped-body arguments-option)
374 (let* ((intercept-lambda-list
375 (gathering1 (collecting)
376 (dolist (arg arguments-option)
377 (if (memq arg lambda-list-keywords)
379 (gather1 (gensym))))))
380 (intercept-rebindings
381 (gathering1 (collecting)
382 (iterate ((arg (list-elements arguments-option))
383 (int (list-elements intercept-lambda-list)))
384 (unless (memq arg lambda-list-keywords)
385 (gather1 `(,arg ',int)))))))
387 (setf (cadr wrapped-body)
388 (append intercept-rebindings (cadr wrapped-body)))
390 ;; Be sure to fill out the intercept lambda list so that it can
391 ;; be too short if it wants to.
392 (cond ((memq '&rest intercept-lambda-list))
393 ((memq '&allow-other-keys intercept-lambda-list))
394 ((memq '&key intercept-lambda-list)
395 (setq intercept-lambda-list
396 (append intercept-lambda-list '(&allow-other-keys))))
398 (setq intercept-lambda-list
399 (append intercept-lambda-list '(&rest .ignore.)))))
401 `(let ((inner-result. ,wrapped-body))
402 `(apply #'(lambda ,',intercept-lambda-list
403 ,,(when (memq '.ignore. intercept-lambda-list)
404 ''(declare (ignore .ignore.)))
406 .combined-method-args.))))