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6 ;;;; to the software are in the public domain and are provided with
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10 ;;;; copyright information from original PCL sources:
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* ((pathname *load-pathname*)
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) ,pathname)))
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))
127 (order (car (method-combination-options combin)))
130 (dolist (m applicable-methods)
131 (let ((qualifiers (method-qualifiers m)))
132 (flet ((lose (method why)
133 (invalid-method-error
135 "The method ~S ~A.~%~
136 The method combination type ~S was defined with the~%~
137 short form of DEFINE-METHOD-COMBINATION and so requires~%~
138 all methods have either the single qualifier ~S or the~%~
139 single qualifier :AROUND."
140 method why type type)))
141 (cond ((null qualifiers)
142 (lose m "has no qualifiers"))
144 (lose m "has more than one qualifier"))
145 ((eq (car qualifiers) :around)
147 ((eq (car qualifiers) type)
150 (lose m "has an illegal qualifier"))))))
151 (setq around (nreverse around))
153 (:most-specific-last) ; nothing to be done, already in correct order
154 (:most-specific-first
155 (setq primary (nreverse primary))))
157 (if (and (null (cdr primary))
159 `(call-method ,(car primary) ())
160 `(,operator ,@(mapcar (lambda (m) `(call-method ,m ()))
162 (cond ((null primary)
163 `(error "No ~S methods for the generic function ~S."
164 ',type ',generic-function))
165 ((null around) main-method)
167 `(call-method ,(car around)
168 (,@(cdr around) (make-method ,main-method))))))))
170 ;;;; long method combinations
172 (defclass long-method-combination (standard-method-combination)
173 ((function :initarg :function
174 :reader long-method-combination-function)))
176 (defun expand-long-defcombin (form)
177 (let ((type (cadr form))
178 (lambda-list (caddr form))
179 (method-group-specifiers (cadddr form))
183 (when (and (consp (car body)) (eq (caar body) :arguments))
184 (setq args-option (cdr (pop body))))
185 (when (and (consp (car body)) (eq (caar body) :generic-function))
186 (setq gf-var (cadr (pop body))))
187 (multiple-value-bind (documentation function)
188 (make-long-method-combination-function
189 type lambda-list method-group-specifiers args-option gf-var
191 `(load-long-defcombin ',type ',documentation #',function))))
193 (defvar *long-method-combination-functions* (make-hash-table :test 'eq))
195 (defun load-long-defcombin (type doc function)
197 (list (find-class 'generic-function)
198 (intern-eql-specializer type)
201 (get-method #'find-method-combination () specializers nil))
203 (make-instance 'standard-method
205 :specializers specializers
206 :lambda-list '(generic-function type options)
207 :function (lambda (args nms &rest cm-args)
208 (declare (ignore nms cm-args))
210 (lambda (generic-function type options)
211 (declare (ignore generic-function))
212 (make-instance 'long-method-combination
217 :definition-source `((define-method-combination ,type)
219 (setf (gethash type *long-method-combination-functions*) function)
220 (when old-method (remove-method #'find-method-combination old-method))
221 (add-method #'find-method-combination new-method)))
223 (defmethod compute-effective-method ((generic-function generic-function)
224 (combin long-method-combination)
226 (funcall (gethash (method-combination-type combin)
227 *long-method-combination-functions*)
232 (defun make-long-method-combination-function
233 (type ll method-group-specifiers args-option gf-var body)
234 (declare (ignore type))
235 (multiple-value-bind (real-body declarations documentation)
236 ;; (Note that PARSE-BODY ignores its second arg ENVIRONMENT.)
237 (parse-body body nil)
240 (wrap-method-group-specifier-bindings method-group-specifiers
244 (push `(,gf-var .generic-function.) (cadr wrapped-body)))
247 (setq wrapped-body (deal-with-args-option wrapped-body args-option)))
251 `(apply #'(lambda ,ll ,wrapped-body)
252 (method-combination-options .method-combination.))))
256 `(lambda (.generic-function. .method-combination. .applicable-methods.)
257 (progn .generic-function. .method-combination. .applicable-methods.)
258 (block .long-method-combination-function. ,wrapped-body))))))
260 ;; parse-method-group-specifiers parse the method-group-specifiers
262 (defun wrap-method-group-specifier-bindings
263 (method-group-specifiers declarations real-body)
269 (dolist (method-group-specifier method-group-specifiers)
270 (multiple-value-bind (name tests description order required)
271 (parse-method-group-specifier method-group-specifier)
272 (declare (ignore description))
273 (let ((specializer-cache (gensym)))
275 (push specializer-cache specializer-caches)
277 (if (and (equal ,specializer-cache .specializers.)
278 (not (null .specializers.)))
279 (return-from .long-method-combination-function.
280 '(error "More than one method of type ~S ~
281 with the same specializers."
283 (setq ,specializer-cache .specializers.))
284 (push .method. ,name))
287 (push `(when (null ,name)
288 (return-from .long-method-combination-function.
289 '(error "No ~S methods." ',name)))
291 (loop (unless (and (constantp order)
292 (neq order (setq order (eval order))))
294 (push (cond ((eq order :most-specific-first)
295 `(setq ,name (nreverse ,name)))
296 ((eq order :most-specific-last) ())
299 (:most-specific-first
300 (setq ,name (nreverse ,name)))
301 (:most-specific-last))))
303 `(let (,@(nreverse names) ,@(nreverse specializer-caches))
305 (dolist (.method. .applicable-methods.)
306 (let ((.qualifiers. (method-qualifiers .method.))
307 (.specializers. (method-specializers .method.)))
308 (declare (ignorable .qualifiers. .specializers.))
309 (cond ,@(nreverse cond-clauses))))
310 ,@(nreverse required-checks)
311 ,@(nreverse order-cleanups)
314 (defun parse-method-group-specifier (method-group-specifier)
315 ;;(declare (values name tests description order required))
316 (let* ((name (pop method-group-specifier))
322 (if (or (null method-group-specifier)
323 (memq (car method-group-specifier)
324 '(:description :order :required)))
325 (return-from collect-tests t)
326 (let ((pattern (pop method-group-specifier)))
327 (push pattern patterns)
328 (push (parse-qualifier-pattern name pattern)
330 (nreverse collect))))
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-args-option (wrapped-body args-option)
374 (let* ((intercept-lambda-list
376 (dolist (arg args-option)
377 (if (memq arg lambda-list-keywords)
379 (push (gensym) collect)))
381 (intercept-rebindings
382 (loop for arg in args-option
383 for int in intercept-lambda-list
384 unless (memq arg lambda-list-keywords)
385 collect `(,arg ',int))))
386 (setf (cadr wrapped-body)
387 (append intercept-rebindings (cadr wrapped-body)))
389 ;; Be sure to fill out the intercept lambda list so that it can
390 ;; be too short if it wants to.
391 (cond ((memq '&rest intercept-lambda-list))
392 ((memq '&allow-other-keys intercept-lambda-list))
393 ((memq '&key intercept-lambda-list)
394 (setq intercept-lambda-list
395 (append intercept-lambda-list '(&allow-other-keys))))
397 (setq intercept-lambda-list
398 (append intercept-lambda-list '(&rest .ignore.)))))
400 `(let ((inner-result. ,wrapped-body))
401 `(apply #'(lambda ,',intercept-lambda-list
402 ,,(when (memq '.ignore. intercept-lambda-list)
403 ''(declare (ignore .ignore.)))
405 .combined-method-args.))))