X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fpcl%2Fdefcombin.lisp;h=c4dc44981d0e36f208ef310bc5b3d4a95f4115f0;hb=961c6bf2eda5d492d5dbb7e275fe4e0931f7adf8;hp=342f98f2f195fc94233773985956e179c441dc97;hpb=cea4896b2482b7b2b429c1631d774b4cfbc0efba;p=sbcl.git

diff --git a/src/pcl/defcombin.lisp b/src/pcl/defcombin.lisp
index 342f98f..c4dc449 100644
--- a/src/pcl/defcombin.lisp
+++ b/src/pcl/defcombin.lisp
@@ -25,28 +25,28 @@
 
 (defmacro define-method-combination (&whole form &rest args)
   (declare (ignore args))
-  (if (and (cddr form)
-	   (listp (caddr form)))
-      (expand-long-defcombin form)
-      (expand-short-defcombin form)))
+  `(progn
+     (with-single-package-locked-error
+         (:symbol ',(second form) "defining ~A as a method combination"))
+     ,(if (and (cddr form)
+               (listp (caddr form)))
+          (expand-long-defcombin form)
+          (expand-short-defcombin form))))
 
 ;;;; standard method combination
 
-;;; The STANDARD method combination type is implemented directly by the class
-;;; STANDARD-METHOD-COMBINATION. The method on COMPUTE-EFFECTIVE-METHOD does
-;;; standard method combination directly and is defined by hand in the file
-;;; combin.lisp. The method for FIND-METHOD-COMBINATION must appear in this
-;;; file for bootstrapping reasons.
-;;;
-;;; A commented out copy of this definition appears in combin.lisp.
-;;; If you change this definition here, be sure to change it there
-;;; also.
+;;; The STANDARD method combination type is implemented directly by
+;;; the class STANDARD-METHOD-COMBINATION. The method on
+;;; COMPUTE-EFFECTIVE-METHOD does standard method combination directly
+;;; and is defined by hand in the file combin.lisp. The method for
+;;; FIND-METHOD-COMBINATION must appear in this file for bootstrapping
+;;; reasons.
 (defmethod find-method-combination ((generic-function generic-function)
-				    (type (eql 'standard))
-				    options)
+                                    (type-name (eql 'standard))
+                                    options)
   (when options
     (method-combination-error
-      "The method combination type STANDARD accepts no options."))
+      "STANDARD method combination accepts no options."))
   *standard-method-combination*)
 
 ;;;; short method combinations
@@ -56,311 +56,371 @@
 ;;;; method combination object just reads the parameters out of the object
 ;;;; and runs the same rule.
 
-(defclass short-method-combination (standard-method-combination)
-     ((operator
-	:reader short-combination-operator
-	:initarg :operator)
-      (identity-with-one-argument
-	:reader short-combination-identity-with-one-argument
-	:initarg :identity-with-one-argument))
-  (:predicate-name short-method-combination-p))
-
 (defun expand-short-defcombin (whole)
-  (let* ((type (cadr whole))
-	 (documentation
-	   (getf (cddr whole) :documentation ""))
-	 (identity-with-one-arg
-	   (getf (cddr whole) :identity-with-one-argument nil))
-	 (operator
-	   (getf (cddr whole) :operator type)))
-    (make-top-level-form `(define-method-combination ,type)
-			 '(:load-toplevel :execute)
-      `(load-short-defcombin
-	 ',type ',operator ',identity-with-one-arg ',documentation))))
+  (let* ((type-name (cadr whole))
+         (documentation
+           (getf (cddr whole) :documentation))
+         (identity-with-one-arg
+           (getf (cddr whole) :identity-with-one-argument nil))
+         (operator
+           (getf (cddr whole) :operator type-name)))
+    `(load-short-defcombin
+     ',type-name ',operator ',identity-with-one-arg ',documentation
+      (sb-c:source-location))))
 
-(defun load-short-defcombin (type operator ioa doc)
-  (let* ((truename *load-truename*)
-	 (specializers
-	   (list (find-class 'generic-function)
-		 (intern-eql-specializer type)
-		 *the-class-t*))
-	 (old-method
-	   (get-method #'find-method-combination () specializers nil))
-	 (new-method nil))
+(defun load-short-defcombin (type-name operator ioa doc source-location)
+  (let* ((specializers
+           (list (find-class 'generic-function)
+                 (intern-eql-specializer type-name)
+                 *the-class-t*))
+         (old-method
+           (get-method #'find-method-combination () specializers nil))
+         (new-method nil))
     (setq new-method
-	  (make-instance 'standard-method
-	    :qualifiers ()
-	    :specializers specializers
-	    :lambda-list '(generic-function type options)
-	    :function #'(lambda(args nms &rest cm-args)
-			  (declare (ignore nms cm-args))
-			  (apply
-			   #'(lambda (gf type options)
-			       (declare (ignore gf))
-			       (do-short-method-combination
-				type options operator ioa new-method doc))
-			   args))
-	    :definition-source `((define-method-combination ,type) ,truename)))
+          (make-instance 'standard-method
+            :qualifiers ()
+            :specializers specializers
+            :lambda-list '(generic-function type-name options)
+            :function (lambda (args nms &rest cm-args)
+                        (declare (ignore nms cm-args))
+                        (apply
+                         (lambda (gf type-name options)
+                           (declare (ignore gf))
+                           (short-combine-methods
+                            type-name options operator ioa new-method doc))
+                         args))
+            :definition-source source-location))
     (when old-method
       (remove-method #'find-method-combination old-method))
-    (add-method #'find-method-combination new-method)))
+    (add-method #'find-method-combination new-method)
+    (setf (random-documentation type-name 'method-combination) doc)
+    type-name))
 
-(defun do-short-method-combination (type options operator ioa method doc)
+(defun short-combine-methods (type-name options operator ioa method doc)
   (cond ((null options) (setq options '(:most-specific-first)))
-	((equal options '(:most-specific-first)))
-	((equal options '(:most-specific-last)))
-	(t
-	 (method-combination-error
-	   "Illegal options to a short method combination type.~%~
-	    The method combination type ~S accepts one option which~%~
-	    must be either :MOST-SPECIFIC-FIRST or :MOST-SPECIFIC-LAST."
-	   type)))
+        ((equal options '(:most-specific-first)))
+        ((equal options '(:most-specific-last)))
+        (t
+         (method-combination-error
+          "Illegal options to a short method combination type.~%~
+           The method combination type ~S accepts one option which~%~
+           must be either :MOST-SPECIFIC-FIRST or :MOST-SPECIFIC-LAST."
+          type-name)))
   (make-instance 'short-method-combination
-		 :type type
-		 :options options
-		 :operator operator
-		 :identity-with-one-argument ioa
-		 :definition-source method
-		 :documentation doc))
+                 :type-name type-name
+                 :options options
+                 :operator operator
+                 :identity-with-one-argument ioa
+                 :definition-source method
+                 :documentation doc))
 
 (defmethod compute-effective-method ((generic-function generic-function)
-				     (combin short-method-combination)
-				     applicable-methods)
-  (let ((type (method-combination-type combin))
-	(operator (short-combination-operator combin))
-	(ioa (short-combination-identity-with-one-argument combin))
-	(around ())
-	(primary ()))
-    (dolist (m applicable-methods)
-      (let ((qualifiers (method-qualifiers m)))
-	(flet ((lose (method why)
-		 (invalid-method-error
-		   method
-		   "The method ~S ~A.~%~
-		    The method combination type ~S was defined with the~%~
-		    short form of DEFINE-METHOD-COMBINATION and so requires~%~
-		    all methods have either the single qualifier ~S or the~%~
-		    single qualifier :AROUND."
-		   method why type type)))
-	  (cond ((null qualifiers)
-		 (lose m "has no qualifiers"))
-		((cdr qualifiers)
-		 (lose m "has more than one qualifier"))
-		((eq (car qualifiers) :around)
-		 (push m around))
-		((eq (car qualifiers) type)
-		 (push m primary))
-		(t
-		 (lose m "has an illegal qualifier"))))))
-    (setq around (nreverse around)
-	  primary (nreverse primary))
+                                     (combin short-method-combination)
+                                     applicable-methods)
+  (let ((type-name (method-combination-type-name combin))
+        (operator (short-combination-operator combin))
+        (ioa (short-combination-identity-with-one-argument combin))
+        (order (car (method-combination-options combin)))
+        (around ())
+        (primary ()))
+    (flet ((invalid (gf combin m)
+             (return-from compute-effective-method
+               `(%invalid-qualifiers ',gf ',combin ',m))))
+      (dolist (m applicable-methods)
+        (let ((qualifiers (method-qualifiers m)))
+          (cond ((null qualifiers) (invalid generic-function combin m))
+                ((cdr qualifiers) (invalid generic-function combin m))
+                ((eq (car qualifiers) :around)
+                 (push m around))
+                ((eq (car qualifiers) type-name)
+                 (push m primary))
+                (t (invalid generic-function combin m))))))
+    (setq around (nreverse around))
+    (ecase order
+      (:most-specific-last) ; nothing to be done, already in correct order
+      (:most-specific-first
+       (setq primary (nreverse primary))))
     (let ((main-method
-	    (if (and (null (cdr primary))
-		     (not (null ioa)))
-		`(call-method ,(car primary) ())
-		`(,operator ,@(mapcar #'(lambda (m) `(call-method ,m ()))
-				      primary)))))
+            (if (and (null (cdr primary))
+                     (not (null ioa)))
+                `(call-method ,(car primary) ())
+                `(,operator ,@(mapcar (lambda (m) `(call-method ,m ()))
+                                      primary)))))
       (cond ((null primary)
-	     `(error "No ~S methods for the generic function ~S."
-		     ',type ',generic-function))
-	    ((null around) main-method)
-	    (t
-	     `(call-method ,(car around)
-			   (,@(cdr around) (make-method ,main-method))))))))
+             ;; As of sbcl-0.8.0.80 we don't seem to need to need
+             ;; to do anything messy like
+             ;;        `(APPLY (FUNCTION (IF AROUND
+             ;;                              'NO-PRIMARY-METHOD
+             ;;                              'NO-APPLICABLE-METHOD)
+             ;;                           ',GENERIC-FUNCTION
+             ;;                           .ARGS.)
+             ;; here because (for reasons I don't understand at the
+             ;; moment -- WHN) control will never reach here if there
+             ;; are no applicable methods, but instead end up
+             ;; in NO-APPLICABLE-METHODS first.
+             ;;
+             ;; FIXME: The way that we arrange for .ARGS. to be bound
+             ;; here seems weird. We rely on EXPAND-EFFECTIVE-METHOD-FUNCTION
+             ;; recognizing any form whose operator is %NO-PRIMARY-METHOD
+             ;; as magical, and carefully surrounding it with a
+             ;; LAMBDA form which binds .ARGS. But...
+             ;;   1. That seems fragile, because the magicalness of
+             ;;      %NO-PRIMARY-METHOD forms is scattered around
+             ;;      the system. So it could easily be broken by
+             ;;      locally-plausible maintenance changes like,
+             ;;      e.g., using the APPLY expression above.
+             ;;   2. That seems buggy w.r.t. to MOPpish tricks in
+             ;;      user code, e.g.
+             ;;         (DEFMETHOD COMPUTE-EFFECTIVE-METHOD :AROUND (...)
+             ;;           `(PROGN ,(CALL-NEXT-METHOD) (INCF *MY-CTR*)))
+             `(%no-primary-method ',generic-function .args.))
+            ((null around) main-method)
+            (t
+             `(call-method ,(car around)
+                           (,@(cdr around) (make-method ,main-method))))))))
+
+(defmethod invalid-qualifiers ((gf generic-function)
+                               (combin short-method-combination)
+                               method)
+  (let ((qualifiers (method-qualifiers method))
+        (type-name (method-combination-type-name combin)))
+    (let ((why (cond
+                 ((null qualifiers) "has no qualifiers")
+                 ((cdr qualifiers) "has too many qualifiers")
+                 (t (aver (and (neq (car qualifiers) type-name)
+                               (neq (car qualifiers) :around)))
+                    "has an invalid qualifier"))))
+      (invalid-method-error
+       method
+       "The method ~S on ~S ~A.~%~
+        The method combination type ~S was defined with the~%~
+        short form of DEFINE-METHOD-COMBINATION and so requires~%~
+        all methods have either the single qualifier ~S or the~%~
+        single qualifier :AROUND."
+       method gf why type-name type-name))))
 
 ;;;; long method combinations
 
-(defclass long-method-combination (standard-method-combination)
-     ((function :initarg :function
-		:reader long-method-combination-function)))
-
 (defun expand-long-defcombin (form)
-  (let ((type (cadr form))
-	(lambda-list (caddr form))
-	(method-group-specifiers (cadddr form))
-	(body (cddddr form))
-	(arguments-option ())
-	(gf-var nil))
+  (let ((type-name (cadr form))
+        (lambda-list (caddr form))
+        (method-group-specifiers (cadddr form))
+        (body (cddddr form))
+        (args-option ())
+        (gf-var nil))
     (when (and (consp (car body)) (eq (caar body) :arguments))
-      (setq arguments-option (cdr (pop body))))
+      (setq args-option (cdr (pop body))))
     (when (and (consp (car body)) (eq (caar body) :generic-function))
       (setq gf-var (cadr (pop body))))
     (multiple-value-bind (documentation function)
-	(make-long-method-combination-function
-	  type lambda-list method-group-specifiers arguments-option gf-var
-	  body)
-      (make-top-level-form `(define-method-combination ,type)
-			   '(:load-toplevel :execute)
-	`(load-long-defcombin ',type ',documentation #',function)))))
+        (make-long-method-combination-function
+          type-name lambda-list method-group-specifiers args-option gf-var
+          body)
+      `(load-long-defcombin ',type-name ',documentation #',function
+                            ',args-option (sb-c:source-location)))))
 
 (defvar *long-method-combination-functions* (make-hash-table :test 'eq))
 
-(defun load-long-defcombin (type doc function)
+(defun load-long-defcombin
+    (type-name doc function args-lambda-list source-location)
   (let* ((specializers
-	   (list (find-class 'generic-function)
-		 (intern-eql-specializer type)
-		 *the-class-t*))
-	 (old-method
-	   (get-method #'find-method-combination () specializers nil))
-	 (new-method
-	   (make-instance 'standard-method
-	     :qualifiers ()
-	     :specializers specializers
-	     :lambda-list '(generic-function type options)
-	     :function #'(lambda (args nms &rest cm-args)
-			   (declare (ignore nms cm-args))
-			   (apply
-			    #'(lambda (generic-function type options)
-				(declare (ignore generic-function options))
-				(make-instance 'long-method-combination
-					       :type type
-					       :documentation doc))
-			    args))
-	 :definition-source `((define-method-combination ,type)
-			      ,*load-truename*))))
-    (setf (gethash type *long-method-combination-functions*) function)
+           (list (find-class 'generic-function)
+                 (intern-eql-specializer type-name)
+                 *the-class-t*))
+         (old-method
+           (get-method #'find-method-combination () specializers nil))
+         (new-method
+           (make-instance 'standard-method
+             :qualifiers ()
+             :specializers specializers
+             :lambda-list '(generic-function type-name options)
+             :function (lambda (args nms &rest cm-args)
+                         (declare (ignore nms cm-args))
+                         (apply
+                          (lambda (generic-function type-name options)
+                            (declare (ignore generic-function))
+                            (make-instance 'long-method-combination
+                                           :type-name type-name
+                                           :options options
+                                           :args-lambda-list args-lambda-list
+                                           :documentation doc))
+                          args))
+             :definition-source source-location)))
+    (setf (gethash type-name *long-method-combination-functions*) function)
     (when old-method (remove-method #'find-method-combination old-method))
-    (add-method #'find-method-combination new-method)))
+    (add-method #'find-method-combination new-method)
+    (setf (random-documentation type-name 'method-combination) doc)
+    type-name))
 
 (defmethod compute-effective-method ((generic-function generic-function)
-				     (combin long-method-combination)
-				     applicable-methods)
-  (funcall (gethash (method-combination-type combin)
-		    *long-method-combination-functions*)
-	   generic-function
-	   combin
-	   applicable-methods))
+                                     (combin long-method-combination)
+                                     applicable-methods)
+  (funcall (gethash (method-combination-type-name combin)
+                    *long-method-combination-functions*)
+           generic-function
+           combin
+           applicable-methods))
 
 (defun make-long-method-combination-function
-       (type ll method-group-specifiers arguments-option gf-var body)
-  ;;(declare (values documentation function))
-  (declare (ignore type))
-  (multiple-value-bind (documentation declarations real-body)
-      (extract-declarations body)
-
+       (type-name ll method-group-specifiers args-option gf-var body)
+  (declare (ignore type-name))
+  (multiple-value-bind (real-body declarations documentation)
+      (parse-body body)
     (let ((wrapped-body
-	    (wrap-method-group-specifier-bindings method-group-specifiers
-						  declarations
-						  real-body)))
+            (wrap-method-group-specifier-bindings method-group-specifiers
+                                                  declarations
+                                                  real-body)))
       (when gf-var
-	(push `(,gf-var .generic-function.) (cadr wrapped-body)))
+        (push `(,gf-var .generic-function.) (cadr wrapped-body)))
 
-      (when arguments-option
-	(setq wrapped-body (deal-with-arguments-option wrapped-body
-						       arguments-option)))
+      (when args-option
+        (setq wrapped-body (deal-with-args-option wrapped-body args-option)))
 
       (when ll
-	(setq wrapped-body
-	      `(apply #'(lambda ,ll ,wrapped-body)
-		      (method-combination-options .method-combination.))))
+        (setq wrapped-body
+              `(apply #'(lambda ,ll ,wrapped-body)
+                      (method-combination-options .method-combination.))))
 
       (values
-	documentation
-	`(lambda (.generic-function. .method-combination. .applicable-methods.)
-	   (progn .generic-function. .method-combination. .applicable-methods.)
-	   (block .long-method-combination-function. ,wrapped-body))))))
+        documentation
+        `(lambda (.generic-function. .method-combination. .applicable-methods.)
+           (declare (ignorable .generic-function.
+                     .method-combination. .applicable-methods.))
+           (block .long-method-combination-function. ,wrapped-body))))))
 
-;; parse-method-group-specifiers parse the method-group-specifiers
+(define-condition long-method-combination-error
+    (reference-condition simple-error)
+  ()
+  (:default-initargs
+      :references (list '(:ansi-cl :macro define-method-combination))))
+
+;;; NOTE:
+;;;
+;;; The semantics of long form method combination in the presence of
+;;; multiple methods with the same specializers in the same method
+;;; group are unclear by the spec: a portion of the standard implies
+;;; that an error should be signalled, and another is more lenient.
+;;;
+;;; It is reasonable to allow a single method group of * to bypass all
+;;; rules, as this is explicitly stated in the standard.
+
+(defun group-cond-clause (name tests specializer-cache star-only)
+  (let ((maybe-error-clause
+         (if star-only
+             `(setq ,specializer-cache .specializers.)
+             `(if (and (equal ,specializer-cache .specializers.)
+                       (not (null .specializers.)))
+                  (return-from .long-method-combination-function.
+                    '(error 'long-method-combination-error
+                      :format-control "More than one method of type ~S ~
+                                       with the same specializers."
+                      :format-arguments (list ',name)))
+                  (setq ,specializer-cache .specializers.)))))
+    `((or ,@tests)
+      ,maybe-error-clause
+      (push .method. ,name))))
 
 (defun wrap-method-group-specifier-bindings
-       (method-group-specifiers declarations real-body)
-  (with-gathering ((names (collecting))
-		   (specializer-caches (collecting))
-		   (cond-clauses (collecting))
-		   (required-checks (collecting))
-		   (order-cleanups (collecting)))
-      (dolist (method-group-specifier method-group-specifiers)
-	(multiple-value-bind (name tests description order required)
-	    (parse-method-group-specifier method-group-specifier)
-	  (declare (ignore description))
-	  (let ((specializer-cache (gensym)))
-	    (gather name names)
-	    (gather specializer-cache specializer-caches)
-	    (gather `((or ,@tests)
-		      (if  (equal ,specializer-cache .specializers.)
-			   (return-from .long-method-combination-function.
-			     '(error "More than one method of type ~S ~
-				      with the same specializers."
-				     ',name))
-			   (setq ,specializer-cache .specializers.))
-		      (push .method. ,name))
-		    cond-clauses)
-	    (when required
-	      (gather `(when (null ,name)
-			 (return-from .long-method-combination-function.
-			   '(error "No ~S methods." ',name)))
-		      required-checks))
-	    (loop (unless (and (constantp order)
-			       (neq order (setq order (eval order))))
-		    (return t)))
-	    (gather (cond ((eq order :most-specific-first)
-			   `(setq ,name (nreverse ,name)))
-			  ((eq order :most-specific-last) ())
-			  (t
-			   `(ecase ,order
-			      (:most-specific-first
-				(setq ,name (nreverse ,name)))
-			      (:most-specific-last))))
-		    order-cleanups))))
-   `(let (,@names ,@specializer-caches)
-      ,@declarations
-      (dolist (.method. .applicable-methods.)
-	(let ((.qualifiers. (method-qualifiers .method.))
-	      (.specializers. (method-specializers .method.)))
-	  (progn .qualifiers. .specializers.)
-	  (cond ,@cond-clauses)))
-      ,@required-checks
-      ,@order-cleanups
-      ,@real-body)))
+    (method-group-specifiers declarations real-body)
+  (let (names specializer-caches cond-clauses required-checks order-cleanups)
+    (let ((nspecifiers (length method-group-specifiers)))
+      (dolist (method-group-specifier method-group-specifiers
+               (push `(t (return-from .long-method-combination-function.
+                           `(invalid-method-error , .method.
+                             "~@<is applicable, but does not belong ~
+                              to any method group~@:>")))
+                     cond-clauses))
+        (multiple-value-bind (name tests description order required)
+            (parse-method-group-specifier method-group-specifier)
+          (declare (ignore description))
+          (let ((specializer-cache (gensym)))
+            (push name names)
+            (push specializer-cache specializer-caches)
+            (push (group-cond-clause name tests specializer-cache
+                                     (and (eq (cadr method-group-specifier) '*)
+                                          (= nspecifiers 1)))
+                  cond-clauses)
+            (when required
+              (push `(when (null ,name)
+                      (return-from .long-method-combination-function.
+                        '(error 'long-method-combination-error
+                          :format-control "No ~S methods."
+                          :format-arguments (list ',name))))
+                    required-checks))
+            (loop (unless (and (constantp order)
+                               (neq order (setq order
+                                                (constant-form-value order))))
+                    (return t)))
+            (push (cond ((eq order :most-specific-first)
+                         `(setq ,name (nreverse ,name)))
+                        ((eq order :most-specific-last) ())
+                        (t
+                         `(ecase ,order
+                           (:most-specific-first
+                            (setq ,name (nreverse ,name)))
+                           (:most-specific-last))))
+                  order-cleanups))))
+      `(let (,@(nreverse names) ,@(nreverse specializer-caches))
+        ,@declarations
+        (dolist (.method. .applicable-methods.)
+          (let ((.qualifiers. (method-qualifiers .method.))
+                (.specializers. (method-specializers .method.)))
+            (declare (ignorable .qualifiers. .specializers.))
+            (cond ,@(nreverse cond-clauses))))
+        ,@(nreverse required-checks)
+        ,@(nreverse order-cleanups)
+        ,@real-body))))
 
 (defun parse-method-group-specifier (method-group-specifier)
   ;;(declare (values name tests description order required))
   (let* ((name (pop method-group-specifier))
-	 (patterns ())
-	 (tests
-	   (gathering1 (collecting)
-	     (block collect-tests
-	       (loop
-		 (if (or (null method-group-specifier)
-			 (memq (car method-group-specifier)
-			       '(:description :order :required)))
-		     (return-from collect-tests t)
-		     (let ((pattern (pop method-group-specifier)))
-		       (push pattern patterns)
-		       (gather1 (parse-qualifier-pattern name pattern)))))))))
+         (patterns ())
+         (tests
+           (let (collect)
+             (block collect-tests
+               (loop
+                 (if (or (null method-group-specifier)
+                         (memq (car method-group-specifier)
+                               '(:description :order :required)))
+                     (return-from collect-tests t)
+                     (let ((pattern (pop method-group-specifier)))
+                       (push pattern patterns)
+                       (push (parse-qualifier-pattern name pattern)
+                             collect)))))
+             (nreverse collect))))
     (values name
-	    tests
-	    (getf method-group-specifier :description
-		  (make-default-method-group-description patterns))
-	    (getf method-group-specifier :order :most-specific-first)
-	    (getf method-group-specifier :required nil))))
+            tests
+            (getf method-group-specifier :description
+                  (make-default-method-group-description patterns))
+            (getf method-group-specifier :order :most-specific-first)
+            (getf method-group-specifier :required nil))))
 
 (defun parse-qualifier-pattern (name pattern)
   (cond ((eq pattern '()) `(null .qualifiers.))
-	((eq pattern '*) 't)
-	((symbolp pattern) `(,pattern .qualifiers.))
-	((listp pattern) `(qualifier-check-runtime ',pattern .qualifiers.))
-	(t (error "In the method group specifier ~S,~%~
-		   ~S isn't a valid qualifier pattern."
-		  name pattern))))
+        ((eq pattern '*) t)
+        ((symbolp pattern) `(,pattern .qualifiers.))
+        ((listp pattern) `(qualifier-check-runtime ',pattern .qualifiers.))
+        (t (error "In the method group specifier ~S,~%~
+                   ~S isn't a valid qualifier pattern."
+                  name pattern))))
 
 (defun qualifier-check-runtime (pattern qualifiers)
   (loop (cond ((and (null pattern) (null qualifiers))
-	       (return t))
-	      ((eq pattern '*) (return t))
-	      ((and pattern qualifiers (eq (car pattern) (car qualifiers)))
-	       (pop pattern)
-	       (pop qualifiers))
-	      (t (return nil)))))
+               (return t))
+              ((eq pattern '*) (return t))
+              ((and pattern qualifiers (eq (car pattern) (car qualifiers)))
+               (pop pattern)
+               (pop qualifiers))
+              (t (return nil)))))
 
 (defun make-default-method-group-description (patterns)
   (if (cdr patterns)
       (format nil
-	      "methods matching one of the patterns: ~{~S, ~} ~S"
-	      (butlast patterns) (car (last patterns)))
+              "methods matching one of the patterns: ~{~S, ~} ~S"
+              (butlast patterns) (car (last patterns)))
       (format nil
-	      "methods matching the pattern: ~S"
-	      (car patterns))))
+              "methods matching the pattern: ~S"
+              (car patterns))))
 
 ;;; This baby is a complete mess. I can't believe we put it in this
 ;;; way. No doubt this is a large part of what drives MLY crazy.
@@ -370,37 +430,115 @@
 ;;;
 ;;; At compute-effective-method time, the symbols in the :arguments
 ;;; option are bound to the symbols in the intercept lambda list.
-(defun deal-with-arguments-option (wrapped-body arguments-option)
-  (let* ((intercept-lambda-list
-	   (gathering1 (collecting)
-	     (dolist (arg arguments-option)
-	       (if (memq arg lambda-list-keywords)
-		   (gather1 arg)
-		   (gather1 (gensym))))))
-	 (intercept-rebindings
-	   (gathering1 (collecting)
-	     (iterate ((arg (list-elements arguments-option))
-		       (int (list-elements intercept-lambda-list)))
-	       (unless (memq arg lambda-list-keywords)
-		 (gather1 `(,arg ',int)))))))
-
-    (setf (cadr wrapped-body)
-	  (append intercept-rebindings (cadr wrapped-body)))
+;;;
+;;; FIXME: in here we have not one but two mini-copies of a weird
+;;; hybrid of PARSE-LAMBDA-LIST and PARSE-DEFMACRO-LAMBDA-LIST.
+(defun deal-with-args-option (wrapped-body args-lambda-list)
+  (let ((intercept-rebindings
+         (let (rebindings)
+           (dolist (arg args-lambda-list (nreverse rebindings))
+             (unless (member arg lambda-list-keywords :test #'eq)
+               (typecase arg
+                 (symbol (push `(,arg ',arg) rebindings))
+                 (cons
+                  (unless (symbolp (car arg))
+                    (error "invalid lambda-list specifier: ~S." arg))
+                  (push `(,(car arg) ',(car arg)) rebindings))
+                 (t (error "invalid lambda-list-specifier: ~S." arg)))))))
+        (nreq 0)
+        (nopt 0)
+        (whole nil))
+    ;; Count the number of required and optional parameters in
+    ;; ARGS-LAMBDA-LIST into NREQ and NOPT, and set WHOLE to the
+    ;; name of a &WHOLE parameter, if any.
+    (when (member '&whole (rest args-lambda-list))
+      (error 'simple-program-error
+             :format-control "~@<The value of the :ARGUMENTS option of ~
+                DEFINE-METHOD-COMBINATION is~2I~_~S,~I~_but &WHOLE may ~
+                only appear first in the lambda list.~:>"
+             :format-arguments (list args-lambda-list)))
+    (loop with state = 'required
+          for arg in args-lambda-list do
+            (if (memq arg lambda-list-keywords)
+                (setq state arg)
+                (case state
+                  (required (incf nreq))
+                  (&optional (incf nopt))
+                  (&whole (setq whole arg state 'required)))))
+    ;; This assumes that the head of WRAPPED-BODY is a let, and it
+    ;; injects let-bindings of the form (ARG 'SYM) for all variables
+    ;; of the argument-lambda-list; SYM is a gensym.
+    (aver (memq (first wrapped-body) '(let let*)))
+    (setf (second wrapped-body)
+          (append intercept-rebindings (second wrapped-body)))
+    ;; Be sure to fill out the args lambda list so that it can be too
+    ;; short if it wants to.
+    (unless (or (memq '&rest args-lambda-list)
+                (memq '&allow-other-keys args-lambda-list))
+      (let ((aux (memq '&aux args-lambda-list)))
+        (setq args-lambda-list
+              (append (ldiff args-lambda-list aux)
+                      (if (memq '&key args-lambda-list)
+                          '(&allow-other-keys)
+                          '(&rest .ignore.))
+                      aux))))
+    ;; .GENERIC-FUNCTION. is bound to the generic function in the
+    ;; method combination function, and .GF-ARGS* is bound to the
+    ;; generic function arguments in effective method functions
+    ;; created for generic functions having a method combination that
+    ;; uses :ARGUMENTS.
+    ;;
+    ;; The DESTRUCTURING-BIND binds the parameters of the
+    ;; ARGS-LAMBDA-LIST to actual generic function arguments.  Because
+    ;; ARGS-LAMBDA-LIST may be shorter or longer than the generic
+    ;; function's lambda list, which is only known at run time, this
+    ;; destructuring has to be done on a slighly modified list of
+    ;; actual arguments, from which values might be stripped or added.
+    ;;
+    ;; Using one of the variable names in the body inserts a symbol
+    ;; into the effective method, and running the effective method
+    ;; produces the value of actual argument that is bound to the
+    ;; symbol.
+    `(let ((inner-result. ,wrapped-body)
+           (gf-lambda-list (generic-function-lambda-list .generic-function.)))
+       `(destructuring-bind ,',args-lambda-list
+            (frob-combined-method-args
+             .gf-args. ',gf-lambda-list
+             ,',nreq ,',nopt)
+          ,,(when (memq '.ignore. args-lambda-list)
+              ''(declare (ignore .ignore.)))
+          ;; If there is a &WHOLE in the args-lambda-list, let
+          ;; it result in the actual arguments of the generic-function
+          ;; not the frobbed list.
+          ,,(when whole
+              ``(setq ,',whole .gf-args.))
+          ,inner-result.))))
 
-    ;; Be sure to fill out the intercept lambda list so that it can
-    ;; be too short if it wants to.
-    (cond ((memq '&rest intercept-lambda-list))
-	  ((memq '&allow-other-keys intercept-lambda-list))
-	  ((memq '&key intercept-lambda-list)
-	   (setq intercept-lambda-list
-		 (append intercept-lambda-list '(&allow-other-keys))))
-	  (t
-	   (setq intercept-lambda-list
-		 (append intercept-lambda-list '(&rest .ignore.)))))
+;;; Partition VALUES into three sections: required, optional, and the
+;;; rest, according to required, optional, and other parameters in
+;;; LAMBDA-LIST.  Make the required and optional sections NREQ and
+;;; NOPT elements long by discarding values or adding NILs.  Value is
+;;; the concatenated list of required and optional sections, and what
+;;; is left as rest from VALUES.
+(defun frob-combined-method-args (values lambda-list nreq nopt)
+  (loop with section = 'required
+        for arg in lambda-list
+        if (memq arg lambda-list-keywords) do
+          (setq section arg)
+          (unless (eq section '&optional)
+            (loop-finish))
+        else if (eq section 'required)
+          count t into nr
+          and collect (pop values) into required
+        else if (eq section '&optional)
+          count t into no
+          and collect (pop values) into optional
+        finally
+          (flet ((frob (list n m)
+                   (cond ((> n m) (butlast list (- n m)))
+                         ((< n m) (nconc list (make-list (- m n))))
+                         (t list))))
+            (return (nconc (frob required nr nreq)
+                           (frob optional no nopt)
+                           values)))))
 
-    `(let ((inner-result. ,wrapped-body))
-       `(apply #'(lambda ,',intercept-lambda-list
-		   ,,(when (memq '.ignore. intercept-lambda-list)
-		       ''(declare (ignore .ignore.)))
-		   ,inner-result.)
-	       .combined-method-args.))))