;;;; bootstrapping the meta-braid ;;;; ;;;; The code in this file takes the early definitions that have been ;;;; saved up and actually builds those class objects. This work is ;;;; largely driven off of those class definitions, but the fact that ;;;; STANDARD-CLASS is the class of all metaclasses in the braid is ;;;; built into this code pretty deeply. ;;;; This software is part of the SBCL system. See the README file for ;;;; more information. ;;;; This software is derived from software originally released by Xerox ;;;; Corporation. Copyright and release statements follow. Later modifications ;;;; to the software are in the public domain and are provided with ;;;; absolutely no warranty. See the COPYING and CREDITS files for more ;;;; information. ;;;; copyright information from original PCL sources: ;;;; ;;;; Copyright (c) 1985, 1986, 1987, 1988, 1989, 1990 Xerox Corporation. ;;;; All rights reserved. ;;;; ;;;; Use and copying of this software and preparation of derivative works based ;;;; upon this software are permitted. Any distribution of this software or ;;;; derivative works must comply with all applicable United States export ;;;; control laws. ;;;; ;;;; This software is made available AS IS, and Xerox Corporation makes no ;;;; warranty about the software, its performance or its conformity to any ;;;; specification. (in-package "SB-PCL") (defun allocate-standard-instance (wrapper &optional (slots-init nil slots-init-p)) (let ((instance (%make-standard-instance nil (get-instance-hash-code))) (no-of-slots (wrapper-no-of-instance-slots wrapper))) (setf (std-instance-wrapper instance) wrapper) (setf (std-instance-slots instance) (cond (slots-init-p ;; Inline the slots vector allocation and initialization. (let ((slots (make-array no-of-slots :initial-element 0))) (do ((rem-slots slots-init (rest rem-slots)) (i 0 (1+ i))) ((>= i no-of-slots)) ;endp rem-slots)) (declare (list rem-slots) (type index i)) (setf (aref slots i) (first rem-slots))) slots)) (t (make-array no-of-slots :initial-element +slot-unbound+)))) instance)) (defmacro allocate-standard-funcallable-instance-slots (wrapper &optional slots-init-p slots-init) `(let ((no-of-slots (wrapper-no-of-instance-slots ,wrapper))) ,(if slots-init-p `(if ,slots-init-p (make-array no-of-slots :initial-contents ,slots-init) (make-array no-of-slots :initial-element +slot-unbound+)) `(make-array no-of-slots :initial-element +slot-unbound+)))) (define-condition unset-funcallable-instance-function (reference-condition simple-error) () (:default-initargs :references (list '(:amop :generic-function allocate-instance) '(:amop :function set-funcallable-instance-function)))) (defun allocate-standard-funcallable-instance (wrapper &optional (slots-init nil slots-init-p)) (let ((fin (%make-standard-funcallable-instance nil nil (get-instance-hash-code)))) (set-funcallable-instance-function fin #'(lambda (&rest args) (declare (ignore args)) (error 'unset-funcallable-instance-function :format-control "~@" :format-arguments (list fin)))) (setf (fsc-instance-wrapper fin) wrapper (fsc-instance-slots fin) (allocate-standard-funcallable-instance-slots wrapper slots-init-p slots-init)) fin)) (defun classify-slotds (slotds) (let (instance-slots class-slots custom-slots bootp) (dolist (slotd slotds) (let ((alloc (cond ((consp slotd) ; bootstrap (setf bootp t) :instance) (t (slot-definition-allocation slotd))))) (case alloc (:instance (push slotd instance-slots)) (:class (push slotd class-slots)) (t (push slotd custom-slots))))) (values (if bootp (nreverse instance-slots) (when slotds (sort instance-slots #'< :key #'slot-definition-location))) class-slots custom-slots))) ;;;; BOOTSTRAP-META-BRAID ;;;; ;;;; This function builds the base metabraid from the early class definitions. (defmacro !initial-classes-and-wrappers (&rest classes) `(progn ,@(mapcar (lambda (class) (let ((wr (format-symbol *pcl-package* "~A-WRAPPER" class))) `(setf ,wr ,(if (eq class 'standard-generic-function) '*sgf-wrapper* `(!boot-make-wrapper (early-class-size ',class) ',class)) ,class (allocate-standard-instance ,(if (eq class 'standard-generic-function) 'funcallable-standard-class-wrapper 'standard-class-wrapper)) (wrapper-class ,wr) ,class (find-class ',class) ,class))) classes))) (defun !bootstrap-meta-braid () (let* ((*create-classes-from-internal-structure-definitions-p* nil) standard-class-wrapper standard-class funcallable-standard-class-wrapper funcallable-standard-class slot-class-wrapper slot-class built-in-class-wrapper built-in-class structure-class-wrapper structure-class condition-class-wrapper condition-class standard-direct-slot-definition-wrapper standard-direct-slot-definition standard-effective-slot-definition-wrapper standard-effective-slot-definition class-eq-specializer-wrapper class-eq-specializer standard-generic-function-wrapper standard-generic-function) (!initial-classes-and-wrappers standard-class funcallable-standard-class slot-class built-in-class structure-class condition-class standard-direct-slot-definition standard-effective-slot-definition class-eq-specializer standard-generic-function) ;; First, make a class metaobject for each of the early classes. For ;; each metaobject we also set its wrapper. Except for the class T, ;; the wrapper is always that of STANDARD-CLASS. (dolist (definition *early-class-definitions*) (let* ((name (ecd-class-name definition)) (meta (ecd-metaclass definition)) (wrapper (ecase meta (slot-class slot-class-wrapper) (standard-class standard-class-wrapper) (funcallable-standard-class funcallable-standard-class-wrapper) (built-in-class built-in-class-wrapper) (structure-class structure-class-wrapper) (condition-class condition-class-wrapper))) (class (or (find-class name nil) (allocate-standard-instance wrapper)))) (setf (find-class name) class))) (dolist (definition *early-class-definitions*) (let ((name (ecd-class-name definition)) (meta (ecd-metaclass definition)) (source (ecd-source-location definition)) (direct-supers (ecd-superclass-names definition)) (direct-slots (ecd-canonical-slots definition)) (other-initargs (ecd-other-initargs definition))) (let ((direct-default-initargs (getf other-initargs :direct-default-initargs))) (multiple-value-bind (slots cpl default-initargs direct-subclasses) (early-collect-inheritance name) (let* ((class (find-class name)) (wrapper (cond ((eq class slot-class) slot-class-wrapper) ((eq class standard-class) standard-class-wrapper) ((eq class funcallable-standard-class) funcallable-standard-class-wrapper) ((eq class standard-direct-slot-definition) standard-direct-slot-definition-wrapper) ((eq class standard-effective-slot-definition) standard-effective-slot-definition-wrapper) ((eq class built-in-class) built-in-class-wrapper) ((eq class structure-class) structure-class-wrapper) ((eq class condition-class) condition-class-wrapper) ((eq class class-eq-specializer) class-eq-specializer-wrapper) ((eq class standard-generic-function) standard-generic-function-wrapper) (t (!boot-make-wrapper (length slots) name)))) (proto nil)) (when (eq name t) (setq *the-wrapper-of-t* wrapper)) (set (make-class-symbol name) class) (dolist (slot slots) (unless (eq (getf slot :allocation :instance) :instance) (error "Slot allocation ~S is not supported in bootstrap." (getf slot :allocation)))) (when (wrapper-p wrapper) (setf (wrapper-slots wrapper) slots)) (setq proto (if (eq meta 'funcallable-standard-class) (allocate-standard-funcallable-instance wrapper) (allocate-standard-instance wrapper))) (setq direct-slots (!bootstrap-make-slot-definitions name class direct-slots standard-direct-slot-definition-wrapper nil)) (setq slots (!bootstrap-make-slot-definitions name class slots standard-effective-slot-definition-wrapper t)) (setf (layout-slot-table wrapper) (make-slot-table class slots t)) (when (wrapper-p wrapper) (setf (wrapper-slots wrapper) slots)) (case meta ((standard-class funcallable-standard-class) (!bootstrap-initialize-class meta class name class-eq-specializer-wrapper source direct-supers direct-subclasses cpl wrapper proto direct-slots slots direct-default-initargs default-initargs)) (built-in-class ; *the-class-t* (!bootstrap-initialize-class meta class name class-eq-specializer-wrapper source direct-supers direct-subclasses cpl wrapper proto)) (slot-class ; *the-class-slot-object* (!bootstrap-initialize-class meta class name class-eq-specializer-wrapper source direct-supers direct-subclasses cpl wrapper proto)) (structure-class ; *the-class-structure-object* (!bootstrap-initialize-class meta class name class-eq-specializer-wrapper source direct-supers direct-subclasses cpl wrapper)) (condition-class (!bootstrap-initialize-class meta class name class-eq-specializer-wrapper source direct-supers direct-subclasses cpl wrapper)))))))) (setq **standard-method-classes** (mapcar (lambda (name) (symbol-value (make-class-symbol name))) *standard-method-class-names*)) (let* ((smc-class (find-class 'standard-method-combination)) (smc-wrapper (!bootstrap-get-slot 'standard-class smc-class 'wrapper)) (smc (allocate-standard-instance smc-wrapper))) (flet ((set-slot (name value) (!bootstrap-set-slot 'standard-method-combination smc name value))) (set-slot 'source nil) (set-slot 'type-name 'standard) (set-slot '%documentation "The standard method combination.") (set-slot 'options ())) (setq *standard-method-combination* smc)))) ;;; Initialize a class metaobject. (defun !bootstrap-initialize-class (metaclass-name class name class-eq-wrapper source direct-supers direct-subclasses cpl wrapper &optional (proto nil proto-p) direct-slots slots direct-default-initargs default-initargs) (flet ((classes (names) (mapcar #'find-class names)) (set-slot (slot-name value) (!bootstrap-set-slot metaclass-name class slot-name value))) (set-slot 'name name) (set-slot 'finalized-p t) (set-slot 'source source) (set-slot 'safe-p nil) (set-slot '%type (if (eq class (find-class t)) t ;; FIXME: Could this just be CLASS instead ;; of `(CLASS ,CLASS)? If not, why not? ;; (See also similar expression in ;; SHARED-INITIALIZE :BEFORE (CLASS).) `(class ,class))) (set-slot 'class-eq-specializer (let ((spec (allocate-standard-instance class-eq-wrapper))) (!bootstrap-set-slot 'class-eq-specializer spec '%type `(class-eq ,class)) (!bootstrap-set-slot 'class-eq-specializer spec 'object class) spec)) (set-slot '%class-precedence-list (classes cpl)) (set-slot 'cpl-available-p t) (set-slot 'can-precede-list (classes (cdr cpl))) (set-slot 'incompatible-superclass-list nil) (set-slot 'direct-superclasses (classes direct-supers)) (set-slot 'direct-subclasses (classes direct-subclasses)) (set-slot 'direct-methods (cons nil nil)) (set-slot 'wrapper wrapper) (set-slot '%documentation nil) (set-slot 'plist `(,@(and direct-default-initargs `(direct-default-initargs ,direct-default-initargs)) ,@(and default-initargs `(default-initargs ,default-initargs)))) (when (memq metaclass-name '(standard-class funcallable-standard-class structure-class condition-class slot-class)) (set-slot 'direct-slots direct-slots) (set-slot 'slots slots) (setf (layout-slot-table wrapper) (make-slot-table class slots (member metaclass-name '(standard-class funcallable-standard-class)))) (when (wrapper-p wrapper) (setf (wrapper-slots wrapper) slots))) ;; For all direct superclasses SUPER of CLASS, make sure CLASS is ;; a direct subclass of SUPER. Note that METACLASS-NAME doesn't ;; matter here for the slot DIRECT-SUBCLASSES, since every class ;; inherits the slot from class CLASS. (dolist (super direct-supers) (let* ((super (find-class super)) (subclasses (!bootstrap-get-slot metaclass-name super 'direct-subclasses))) (cond ((eq +slot-unbound+ subclasses) (!bootstrap-set-slot metaclass-name super 'direct-subclasses (list class))) ((not (memq class subclasses)) (!bootstrap-set-slot metaclass-name super 'direct-subclasses (cons class subclasses)))))) (case metaclass-name (structure-class (let ((constructor-sym '|STRUCTURE-OBJECT class constructor|)) (set-slot 'defstruct-form `(defstruct (structure-object (:constructor ,constructor-sym) (:copier nil)))) (set-slot 'defstruct-constructor constructor-sym) (set-slot 'from-defclass-p t) (set-slot 'plist nil) (set-slot 'prototype (funcall constructor-sym)))) (condition-class (set-slot 'prototype (make-condition name))) (t (set-slot 'prototype (if proto-p proto (allocate-standard-instance wrapper))))) class)) (defun !bootstrap-make-slot-definitions (name class slots wrapper effective-p) (let ((index -1)) (mapcar (lambda (slot) (incf index) (!bootstrap-make-slot-definition name class slot wrapper effective-p index)) slots))) (defun !bootstrap-make-slot-definition (name class slot wrapper effective-p index) (let* ((slotd-class-name (if effective-p 'standard-effective-slot-definition 'standard-direct-slot-definition)) (slotd (allocate-standard-instance wrapper)) (slot-name (getf slot :name))) (flet ((get-val (name) (getf slot name)) (set-val (name val) (!bootstrap-set-slot slotd-class-name slotd name val))) (set-val 'name slot-name) (set-val 'initform (get-val :initform)) (set-val 'initfunction (get-val :initfunction)) (set-val 'initargs (get-val :initargs)) (unless effective-p (set-val 'readers (get-val :readers)) (set-val 'writers (get-val :writers))) (set-val 'allocation :instance) (set-val '%type (or (get-val :type) t)) (set-val '%documentation (or (get-val :documentation) "")) (set-val '%class class) (when effective-p (set-val 'location index) (set-val 'accessor-flags 7) (set-val 'info (make-slot-info :reader (make-optimized-std-reader-method-function nil nil slot-name index) :writer (make-optimized-std-writer-method-function nil nil slot-name index) :boundp (make-optimized-std-boundp-method-function nil nil slot-name index)))) (when (and (eq name 'standard-class) (eq slot-name 'slots) effective-p) (setq *the-eslotd-standard-class-slots* slotd)) (when (and (eq name 'funcallable-standard-class) (eq slot-name 'slots) effective-p) (setq *the-eslotd-funcallable-standard-class-slots* slotd)) slotd))) (defun !bootstrap-accessor-definitions (early-p) (let ((*early-p* early-p)) (dolist (definition *early-class-definitions*) (let ((name (ecd-class-name definition)) (meta (ecd-metaclass definition))) (unless (eq meta 'built-in-class) (let ((direct-slots (ecd-canonical-slots definition))) (dolist (slotd direct-slots) (let ((slot-name (getf slotd :name)) (readers (getf slotd :readers)) (writers (getf slotd :writers))) (!bootstrap-accessor-definitions1 name slot-name readers writers nil (ecd-source-location definition)))))))))) (defun !bootstrap-accessor-definition (class-name accessor-name slot-name type source-location) (multiple-value-bind (accessor-class make-method-function arglist specls doc) (ecase type (reader (values 'standard-reader-method #'make-std-reader-method-function (list class-name) (list class-name) "automatically generated reader method")) (writer (values 'standard-writer-method #'make-std-writer-method-function (list 'new-value class-name) (list t class-name) "automatically generated writer method")) (boundp (values 'standard-boundp-method #'make-std-boundp-method-function (list class-name) (list class-name) "automatically generated boundp method"))) (let ((gf (ensure-generic-function accessor-name :lambda-list arglist))) (if (find specls (early-gf-methods gf) :key #'early-method-specializers :test 'equal) (unless (assoc accessor-name *!generic-function-fixups* :test #'equal) (update-dfun gf)) (add-method gf (make-a-method accessor-class () arglist specls (funcall make-method-function class-name slot-name) doc :slot-name slot-name :object-class class-name :method-class-function (constantly (find-class accessor-class)) :definition-source source-location)))))) (defun !bootstrap-accessor-definitions1 (class-name slot-name readers writers boundps source-location) (flet ((do-reader-definition (reader) (!bootstrap-accessor-definition class-name reader slot-name 'reader source-location)) (do-writer-definition (writer) (!bootstrap-accessor-definition class-name writer slot-name 'writer source-location)) (do-boundp-definition (boundp) (!bootstrap-accessor-definition class-name boundp slot-name 'boundp source-location))) (dolist (reader readers) (do-reader-definition reader)) (dolist (writer writers) (do-writer-definition writer)) (dolist (boundp boundps) (do-boundp-definition boundp)))) ;;; FIXME: find a better name. (defun !bootstrap-class-predicates (early-p) (let ((*early-p* early-p)) (dolist (ecp *early-class-predicates*) (let ((class-name (car ecp)) (predicate-name (cadr ecp))) (make-class-predicate (find-class class-name) predicate-name))))) (defun !bootstrap-built-in-classes () ;; First make sure that all the supers listed in ;; *BUILT-IN-CLASS-LATTICE* are themselves defined by ;; *BUILT-IN-CLASS-LATTICE*. This is just to check for typos and ;; other sorts of brainos. (dolist (e *built-in-classes*) (dolist (super (cadr e)) (unless (or (eq super t) (assq super *built-in-classes*)) (error "in *BUILT-IN-CLASSES*: ~S has ~S as a super,~%~ but ~S is not itself a class in *BUILT-IN-CLASSES*." (car e) super super)))) ;; In the first pass, we create a skeletal object to be bound to the ;; class name. (let* ((built-in-class (find-class 'built-in-class)) (built-in-class-wrapper (class-wrapper built-in-class))) (dolist (e *built-in-classes*) (let ((class (allocate-standard-instance built-in-class-wrapper))) (setf (find-class (car e)) class)))) ;; In the second pass, we initialize the class objects. (let ((class-eq-wrapper (class-wrapper (find-class 'class-eq-specializer)))) (dolist (e *built-in-classes*) (destructuring-bind (name supers subs cpl prototype) e (let* ((class (find-class name)) (lclass (find-classoid name)) (wrapper (classoid-layout lclass))) (set (get-built-in-class-symbol name) class) (set (get-built-in-wrapper-symbol name) wrapper) (setf (classoid-pcl-class lclass) class) (!bootstrap-initialize-class 'built-in-class class name class-eq-wrapper nil supers subs (cons name cpl) wrapper prototype)))))) #-sb-fluid (declaim (inline wrapper-of)) (defun wrapper-of (x) (layout-of x)) (defun class-of (x) (wrapper-class* (wrapper-of x))) (defun eval-form (form) (lambda () (eval form))) (defun ensure-non-standard-class (name classoid &optional existing-class) (flet ((ensure (metaclass &optional (slots nil slotsp)) (let ((supers (mapcar #'classoid-name (classoid-direct-superclasses classoid)))) (if slotsp (ensure-class-using-class existing-class name :metaclass metaclass :name name :direct-superclasses supers :direct-slots slots) (ensure-class-using-class existing-class name :metaclass metaclass :name name :direct-superclasses supers)))) (slot-initargs-from-structure-slotd (slotd) (let ((accessor (structure-slotd-accessor-symbol slotd))) `(:name ,(structure-slotd-name slotd) :defstruct-accessor-symbol ,accessor :internal-reader-function ,(structure-slotd-reader-function slotd) :internal-writer-function ,(structure-slotd-writer-function name slotd) :type ,(or (structure-slotd-type slotd) t) :initform ,(structure-slotd-init-form slotd) :initfunction ,(eval-form (structure-slotd-init-form slotd))))) (slot-initargs-from-condition-slot (slot) `(:name ,(condition-slot-name slot) :initargs ,(condition-slot-initargs slot) :readers ,(condition-slot-readers slot) :writers ,(condition-slot-writers slot) ,@(when (condition-slot-initform-p slot) (let ((initform (condition-slot-initform slot)) (initfun (condition-slot-initfunction slot))) `(:initform ',initform :initfunction ,initfun))) :allocation ,(condition-slot-allocation slot) :documentation ,(condition-slot-documentation slot)))) (cond ((structure-type-p name) (ensure 'structure-class (mapcar #'slot-initargs-from-structure-slotd (structure-type-slot-description-list name)))) ((condition-type-p name) (ensure 'condition-class (mapcar #'slot-initargs-from-condition-slot (condition-classoid-slots classoid)))) (t (error "~@<~S is not the name of a class.~@:>" name))))) (defun ensure-deffoo-class (classoid) (let ((class (classoid-pcl-class classoid))) (cond (class (ensure-non-standard-class (class-name class) classoid class)) ((eq 'complete **boot-state**) (ensure-non-standard-class (classoid-name classoid) classoid))))) (pushnew 'ensure-deffoo-class sb-kernel::*defstruct-hooks*) (pushnew 'ensure-deffoo-class sb-kernel::*define-condition-hooks*) ;;; FIXME: only needed during bootstrap (defun make-class-predicate (class name) (let* ((gf (ensure-generic-function name :lambda-list '(object))) (mlist (if (eq **boot-state** 'complete) (early-gf-methods gf) (generic-function-methods gf)))) (unless mlist (unless (eq class *the-class-t*) (let* ((default-method-function #'constantly-nil) (default-method-initargs (list :function default-method-function 'plist '(:constant-value nil))) (default-method (make-a-method 'standard-method () (list 'object) (list *the-class-t*) default-method-initargs "class predicate default method"))) (add-method gf default-method))) (let* ((class-method-function #'constantly-t) (class-method-initargs (list :function class-method-function 'plist '(:constant-value t))) (class-method (make-a-method 'standard-method () (list 'object) (list class) class-method-initargs "class predicate class method"))) (add-method gf class-method))) gf)) ;;; Set the inherits from CPL, and register the layout. This actually ;;; installs the class in the Lisp type system. (defun %update-lisp-class-layout (class layout) ;; Protected by *world-lock* in callers. (let ((classoid (layout-classoid layout)) (olayout (class-wrapper class))) (unless (eq (classoid-layout classoid) layout) (setf (layout-inherits layout) (order-layout-inherits (map 'simple-vector #'class-wrapper (reverse (rest (class-precedence-list class)))))) (register-layout layout :invalidate t) ;; FIXME: I don't think this should be necessary, but without it ;; we are unable to compile (TYPEP foo ') in the ;; same file as the class is defined. If we had environments, ;; then I think the classsoid whould only be associated with the ;; name in that environment... Alternatively, fix the compiler ;; so that TYPEP foo ' is slow but compileable. (let ((name (class-name class))) (when (and name (symbolp name) (eq name (classoid-name classoid))) (setf (find-classoid name) classoid)))))) (defun %set-class-type-translation (class classoid) (when (not (typep classoid 'classoid)) (setq classoid (find-classoid classoid nil))) (etypecase classoid (null) (built-in-classoid (let ((translation (built-in-classoid-translation classoid))) (cond (translation (aver (ctype-p translation)) (setf (info :type :translator class) (lambda (spec) (declare (ignore spec)) translation))) (t (setf (info :type :translator class) (lambda (spec) (declare (ignore spec)) classoid)))))) (classoid (setf (info :type :translator class) (lambda (spec) (declare (ignore spec)) classoid))))) (!bootstrap-meta-braid) (!bootstrap-accessor-definitions t) (!bootstrap-class-predicates t) (!bootstrap-accessor-definitions nil) (!bootstrap-class-predicates nil) (!bootstrap-built-in-classes) (dohash ((name x) sb-kernel::*classoid-cells*) (when (classoid-cell-pcl-class x) (let* ((class (find-class-from-cell name x)) (layout (class-wrapper class)) (lclass (layout-classoid layout)) (lclass-pcl-class (classoid-pcl-class lclass)) (olclass (find-classoid name nil))) (if lclass-pcl-class (aver (eq class lclass-pcl-class)) (setf (classoid-pcl-class lclass) class)) (%update-lisp-class-layout class layout) (cond (olclass (aver (eq lclass olclass))) (t (setf (find-classoid name) lclass))) (%set-class-type-translation class name)))) (setq **boot-state** 'braid) (defmethod no-applicable-method (generic-function &rest args) (error "~@" generic-function args)) (defmethod no-next-method ((generic-function standard-generic-function) (method standard-method) &rest args) (error "~@" generic-function method args)) ;;; An extension to the ANSI standard: in the presence of e.g. a ;;; :BEFORE method, it would seem that going through ;;; NO-APPLICABLE-METHOD is prohibited, as in fact there is an ;;; applicable method. -- CSR, 2002-11-15 (define-condition no-primary-method (reference-condition error) ((generic-function :initarg :generic-function :reader no-primary-method-generic-function) (args :initarg :args :reader no-primary-method-args)) (:report (lambda (c s) (format s "~@" (no-primary-method-generic-function c) (no-primary-method-args c)))) (:default-initargs :references (list '(:ansi-cl :section (7 6 6 2))))) (defmethod no-primary-method (generic-function &rest args) (error 'no-primary-method :generic-function generic-function :args args)) (defmethod invalid-qualifiers ((gf generic-function) combin method) (let ((qualifiers (method-qualifiers method))) (let ((why (cond ((cdr qualifiers) "has too many qualifiers") (t (aver (not (member (car qualifiers) '(:around :before :after)))) "has an invalid qualifier")))) (invalid-method-error method "The method ~S on ~S ~A.~%~ Standard method combination requires all methods to have one~%~ of the single qualifiers :AROUND, :BEFORE and :AFTER or to~%~ have no qualifier at all." method gf why))))