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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)
104 (defun short-combine-methods (type options operator ioa method doc)
105 (cond ((null options) (setq options '(:most-specific-first)))
106 ((equal options '(:most-specific-first)))
107 ((equal options '(:most-specific-last)))
109 (method-combination-error
110 "Illegal options to a short method combination type.~%~
111 The method combination type ~S accepts one option which~%~
112 must be either :MOST-SPECIFIC-FIRST or :MOST-SPECIFIC-LAST."
114 (make-instance 'short-method-combination
118 :identity-with-one-argument ioa
119 :definition-source method
122 (defmethod compute-effective-method ((generic-function generic-function)
123 (combin short-method-combination)
125 (let ((type (method-combination-type combin))
126 (operator (short-combination-operator combin))
127 (ioa (short-combination-identity-with-one-argument combin))
128 (order (car (method-combination-options combin)))
131 (dolist (m applicable-methods)
132 (let ((qualifiers (method-qualifiers m)))
133 (flet ((lose (method why)
134 (invalid-method-error
136 "The method ~S ~A.~%~
137 The method combination type ~S was defined with the~%~
138 short form of DEFINE-METHOD-COMBINATION and so requires~%~
139 all methods have either the single qualifier ~S or the~%~
140 single qualifier :AROUND."
141 method why type type)))
142 (cond ((null qualifiers)
143 (lose m "has no qualifiers"))
145 (lose m "has more than one qualifier"))
146 ((eq (car qualifiers) :around)
148 ((eq (car qualifiers) type)
151 (lose m "has an illegal qualifier"))))))
152 (setq around (nreverse around))
154 (:most-specific-last) ; nothing to be done, already in correct order
155 (:most-specific-first
156 (setq 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))
184 (when (and (consp (car body)) (eq (caar body) :arguments))
185 (setq args-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 args-option gf-var
192 `(load-long-defcombin ',type ',documentation #',function))))
194 (defvar *long-method-combination-functions* (make-hash-table :test 'eq))
196 (defun load-long-defcombin (type doc function)
198 (list (find-class 'generic-function)
199 (intern-eql-specializer type)
202 (get-method #'find-method-combination () specializers nil))
204 (make-instance 'standard-method
206 :specializers specializers
207 :lambda-list '(generic-function type options)
208 :function (lambda (args nms &rest cm-args)
209 (declare (ignore nms cm-args))
211 (lambda (generic-function type options)
212 (declare (ignore generic-function))
213 (make-instance 'long-method-combination
218 :definition-source `((define-method-combination ,type)
220 (setf (gethash type *long-method-combination-functions*) function)
221 (when old-method (remove-method #'find-method-combination old-method))
222 (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 args-option gf-var body)
236 (declare (ignore type))
237 (multiple-value-bind (real-body declarations documentation)
238 ;; (Note that PARSE-BODY ignores its second arg ENVIRONMENT.)
239 (parse-body body nil)
242 (wrap-method-group-specifier-bindings method-group-specifiers
246 (push `(,gf-var .generic-function.) (cadr wrapped-body)))
249 (setq wrapped-body (deal-with-args-option wrapped-body args-option)))
253 `(apply #'(lambda ,ll ,wrapped-body)
254 (method-combination-options .method-combination.))))
258 `(lambda (.generic-function. .method-combination. .applicable-methods.)
259 (progn .generic-function. .method-combination. .applicable-methods.)
260 (block .long-method-combination-function. ,wrapped-body))))))
262 ;; parse-method-group-specifiers parse the method-group-specifiers
264 (defun wrap-method-group-specifier-bindings
265 (method-group-specifiers declarations real-body)
271 (dolist (method-group-specifier method-group-specifiers)
272 (multiple-value-bind (name tests description order required)
273 (parse-method-group-specifier method-group-specifier)
274 (declare (ignore description))
275 (let ((specializer-cache (gensym)))
277 (push specializer-cache specializer-caches)
279 (if (and (equal ,specializer-cache .specializers.)
280 (not (null .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 (push `(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 (push (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 (,@(nreverse names) ,@(nreverse specializer-caches))
307 (dolist (.method. .applicable-methods.)
308 (let ((.qualifiers. (method-qualifiers .method.))
309 (.specializers. (method-specializers .method.)))
310 (declare (ignorable .qualifiers. .specializers.))
311 (cond ,@(nreverse cond-clauses))))
312 ,@(nreverse required-checks)
313 ,@(nreverse order-cleanups)
316 (defun parse-method-group-specifier (method-group-specifier)
317 ;;(declare (values name tests description order required))
318 (let* ((name (pop method-group-specifier))
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 (push (parse-qualifier-pattern name pattern)
332 (nreverse collect))))
335 (getf method-group-specifier :description
336 (make-default-method-group-description patterns))
337 (getf method-group-specifier :order :most-specific-first)
338 (getf method-group-specifier :required nil))))
340 (defun parse-qualifier-pattern (name pattern)
341 (cond ((eq pattern '()) `(null .qualifiers.))
343 ((symbolp pattern) `(,pattern .qualifiers.))
344 ((listp pattern) `(qualifier-check-runtime ',pattern .qualifiers.))
345 (t (error "In the method group specifier ~S,~%~
346 ~S isn't a valid qualifier pattern."
349 (defun qualifier-check-runtime (pattern qualifiers)
350 (loop (cond ((and (null pattern) (null qualifiers))
352 ((eq pattern '*) (return t))
353 ((and pattern qualifiers (eq (car pattern) (car qualifiers)))
358 (defun make-default-method-group-description (patterns)
361 "methods matching one of the patterns: ~{~S, ~} ~S"
362 (butlast patterns) (car (last patterns)))
364 "methods matching the pattern: ~S"
367 ;;; This baby is a complete mess. I can't believe we put it in this
368 ;;; way. No doubt this is a large part of what drives MLY crazy.
370 ;;; At runtime (when the effective-method is run), we bind an intercept
371 ;;; lambda-list to the arguments to the generic function.
373 ;;; At compute-effective-method time, the symbols in the :arguments
374 ;;; option are bound to the symbols in the intercept lambda list.
375 (defun deal-with-args-option (wrapped-body args-option)
376 (let* ((intercept-lambda-list
378 (dolist (arg args-option)
379 (if (memq arg lambda-list-keywords)
381 (push (gensym) collect)))
383 (intercept-rebindings
384 (loop for arg in args-option
385 for int in intercept-lambda-list
386 unless (memq arg lambda-list-keywords)
387 collect `(,arg ',int))))
388 (setf (cadr wrapped-body)
389 (append intercept-rebindings (cadr wrapped-body)))
391 ;; Be sure to fill out the intercept lambda list so that it can
392 ;; be too short if it wants to.
393 (cond ((memq '&rest intercept-lambda-list))
394 ((memq '&allow-other-keys intercept-lambda-list))
395 ((memq '&key intercept-lambda-list)
396 (setq intercept-lambda-list
397 (append intercept-lambda-list '(&allow-other-keys))))
399 (setq intercept-lambda-list
400 (append intercept-lambda-list '(&rest .ignore.)))))
402 `(let ((inner-result. ,wrapped-body))
403 `(apply #'(lambda ,',intercept-lambda-list
404 ,,(when (memq '.ignore. intercept-lambda-list)
405 ''(declare (ignore .ignore.)))
407 .combined-method-args.))))