;;;-*-Mode:LISP; Package: PCL; Base:10; Syntax:Common-lisp -*- ;;; ;;; ************************************************************************* ;;; 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. ;;; ;;; Any person obtaining a copy of this software is requested to send their ;;; name and post office or electronic mail address to: ;;; CommonLoops Coordinator ;;; Xerox PARC ;;; 3333 Coyote Hill Rd. ;;; Palo Alto, CA 94304 ;;; (or send Arpanet mail to CommonLoops-Coordinator.pa@Xerox.arpa) ;;; ;;; Suggestions, comments and requests for improvements are also welcome. ;;; ************************************************************************* ;;; (in-package :pcl) ;;; ;;; DEFINE-METHOD-COMBINATION ;;; (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))) ;;; ;;; 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. ;;; (defmethod find-method-combination ((generic-function generic-function) (type (eql 'standard)) options) (when options (method-combination-error "The method combination type STANDARD accepts no options.")) *standard-method-combination*) ;;; ;;; short method combinations ;;; ;;; Short method combinations all follow the same rule for computing the ;;; effective method. So, we just implement that rule once. Each short ;;; 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 eval) `(load-short-defcombin ',type ',operator ',identity-with-one-arg ',documentation)))) (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)) (setq new-method (make-instance 'standard-method :qualifiers () :specializers specializers :lambda-list '(generic-function type options) :function #'(lambda (gf type options) (declare (ignore gf)) (do-short-method-combination type options operator ioa new-method doc)) :definition-source `((define-method-combination ,type) ,truename))) (when old-method (remove-method #'find-method-combination old-method)) (add-method #'find-method-combination new-method))) (defun do-short-method-combination (type 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))) (make-instance 'short-method-combination :type type :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)) (let ((main-method (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)))))))) ;;; ;;; 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)) (when (and (consp (car body)) (eq (caar body) :arguments)) (setq arguments-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 eval) `(load-long-defcombin ',type ',documentation #',function))))) (defvar *long-method-combination-functions* (make-hash-table :test #'eq)) (defun load-long-defcombin (type doc function) (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 (generic-function type options) (declare (ignore generic-function)) (make-instance 'long-method-combination :type type :documentation doc :options options)) :definition-source `((define-method-combination ,type) ,(load-truename))))) (setf (gethash type *long-method-combination-functions*) function) (when old-method (remove-method #'find-method-combination old-method)) (add-method #'find-method-combination new-method))) (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)) ;;; ;;; ;;; (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) (let ((wrapped-body (wrap-method-group-specifier-bindings method-group-specifiers declarations real-body))) (when gf-var (push `(,gf-var .generic-function.) (cadr wrapped-body))) (when arguments-option (setq wrapped-body (deal-with-arguments-option wrapped-body arguments-option))) (when ll (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)))))) ;; ;; parse-method-group-specifiers parse the method-group-specifiers ;; (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))) (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))))))))) (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)))) (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)))) (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))))) (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))) (format nil "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. ;;; ;;; At runtime (when the effective-method is run), we bind an intercept ;;; lambda-list to the arguments to the generic function. ;;; ;;; 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))) ;; ;; 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.))))) `(let ((inner-result. ,wrapped-body)) `(apply #'(lambda ,',intercept-lambda-list ,,(when (memq '.ignore. intercept-lambda-list) ''(declare (ignore .ignore.))) ,inner-result.) .combined-method-args.))))