ecl/src/clos/method.lsp

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;;;; Copyright (c) 1992, Giuseppe Attardi.
;;;;
;;;; This program is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Library General Public
;;;; License as published by the Free Software Foundation; either
;;;; version 2 of the License, or (at your option) any later version.
;;;;
;;;; See file '../Copyright' for full details.
(in-package "CLOS")
;;; ----------------------------------------------------------------------
(defvar *method-size* 32) ; Size of methods hash tables
;;; This holds fake methods created during bootstrap.
;;; It is an alist of:
;;; (method-name {method}+)
(defvar *early-methods* nil)
;;;
;;; This is used by combined methods to communicate the next methods to
;;; the methods they call.
;;;
(defvar *next-methods* nil)
;;; ----------------------------------------------------------------------
;;; DEFMETHOD
;;;
;;; For setf methods the syntax is:
;;; (defmethod (setf foo) ((nv type) (x1 type1) ... (xn typen))
;;; ...)
;;; where nv is the new value to be assigned.
(defmacro defmethod (&rest args &environment env)
;; args = name {method-qualifier}* specialized-lambda-list &body body
(multiple-value-bind (name qualifiers lambda-list body)
(parse-defmethod args)
(multiple-value-bind (fn-form specializers doc plist)
(expand-defmethod name qualifiers lambda-list body env)
(multiple-value-bind (parameters specialized-lambda-list specializers)
(parse-specialized-lambda-list lambda-list nil)
(declare (ignore parameters))
`(PROGN
#+PDE
(EVAL-WHEN
(LOAD)
(SI:RECORD-SOURCE-PATHNAME
',name '(DEFMETHOD ',qualifiers ',specializers)))
(INSTALL-METHOD
',name
',qualifiers
',specializers
',specialized-lambda-list
',doc
',plist
,fn-form)
)))))
;;; ----------------------------------------------------------------------
;;; method body expansion
(defun expand-defmethod
(generic-function-name qualifiers specialized-lambda-list body env)
;; (values fn-form specializers doc)
(declare (ignore qualifiers)
(si::c-local))
(multiple-value-bind (declarations real-body documentation)
(sys::find-declarations body)
(multiple-value-bind (parameters lambda-list specializers)
(parse-specialized-lambda-list specialized-lambda-list 't)
;; FIXME!! This deactivates the checking of keyword arguments
;; inside methods. The reason is that this checking must be
;; supplemented the knowledge of the keyword arguments of all
;; applicable methods (X3J13 7.6.5). Therefore, we should insert
;; that check, either in the method itself so that it is done
;; incrementally, or in COMPUTE-EFFECTIVE-METHOD.
(when (and (member '&key lambda-list)
(not (member '&allow-other-keys lambda-list)))
(let ((x (position '&aux lambda-list)))
(setf lambda-list
(append (subseq lambda-list 0 x)
'(&allow-other-keys)
(and x (subseq lambda-list x))))))
(let* ((required-parameters
(mapcar #'(lambda (r s) (declare (ignore s)) r)
parameters
specializers))
(class-declarations
`(declare
,@(mapcan #'(lambda (p s) (and (symbolp s) s
(not (eq s 't))
`((type ,s ,p))))
parameters
specializers)))
(method-lambda
;; Remove the documentation string and insert the
;; appropriate class declarations. The documentation
;; string is removed to make it easy for us to insert
;; new declarations later, they will just go after the
;; second of the method lambda. The class declarations
;; are inserted to communicate the class of the method's
;; arguments to the code walk.
`(ext::lambda-block ,generic-function-name
,lambda-list
,class-declarations
,@declarations
,@real-body))
(original-args ())
(applyp nil) ; flag indicating whether or not the
; method takes &mumble arguments. If
; it does, it means call-next-method
; without arguments must be APPLY'd
; to original-args. If this gets set
; true, save-original-args is set so
; as well
(aux-bindings ()) ; Suffice to say that &aux is one of
; damndest things to have put in a
; language.
(slots (mapcar #'list required-parameters))
; records for each class:
; - slot-index-table
; - slot-indexes for each slot
; See optimize-standard-instance-access.
(plist ()))
(multiple-value-bind (walked-lambda call-next-method-p
save-original-args next-method-p-p)
(walk-method-lambda method-lambda required-parameters env slots)
;; Scan the lambda list to determine whether this method
;; takes &mumble arguments. If it does, we set applyp and
;; save-original-args true.
;;
;; This is also the place where we construct the original
;; arguments lambda list if there has to be one.
(dolist (p lambda-list)
(if (member p '(&OPTIONAL &REST &KEY &ALLOW-OTHER-KEYS &AUX)
:test #'eq) ; cant use lambda-list-keywords
(if (eq p '&aux)
(progn
(setq aux-bindings (cdr (member '&AUX lambda-list
:test #'eq)))
(return nil))
(progn
(setq applyp t
save-original-args t)
(push '&REST original-args)
(push (make-symbol "AMPERSAND-ARGS") original-args)
(return nil)))
(push (make-symbol (symbol-name p)) original-args)))
(setq original-args (when save-original-args
(nreverse original-args)))
(multiple-value-bind (walked-declarations walked-lambda-body)
(sys::find-declarations (cdddr walked-lambda) t)
(declare (ignore ignore))
(when (some #'cdr slots) ; there are optimized slot accesses
(setq walked-lambda-body
(add-index-binding walked-lambda-body slots)))
(when (or next-method-p-p call-next-method-p)
(setq plist (list* :needs-next-methods-p 'T plist)))
(values
(let ((walked-lambda `(ext::lambda-block ,(second walked-lambda)
,lambda-list
,@walked-declarations
,.walked-lambda-body)))
(if (or call-next-method-p next-method-p-p)
`(function ,(add-lexical-functions-to-method-lambda
walked-declarations
walked-lambda-body
generic-function-name
walked-lambda
original-args
lambda-list
save-original-args
applyp
aux-bindings
call-next-method-p
next-method-p-p))
`(function ,walked-lambda)))
specializers
documentation
plist)))))))
(defun walk-method-lambda (method-lambda required-parameters env slots)
(declare (si::c-local))
(let ((call-next-method-p nil);flag indicating that call-next-method
;should be in the method definition
(next-method-p-p nil) ;flag indicating that next-method-p
;should be in the method definition
(save-original-args nil);flag indicating whether or not the
;original arguments to the method
;must be preserved. This happens
;for two reasons:
; - the method takes &mumble args,
; so one of the lexical functions
; might be used in a default value
; form
; - call-next-method is used without
; arguments at least once in the
; body of the method
(closurep nil) ;flag indicating whether #'call-next-method
;was seen in the code
)
(flet ((walk-function (form context env)
(cond ((not (eq context ':EVAL)) form)
((not (listp form)) form)
((eq (car form) 'CALL-NEXT-METHOD)
(setq call-next-method-p 'T
save-original-args (not (cdr form)))
form)
((eq (car form) 'NEXT-METHOD-P)
(setq next-method-p-p 'T)
form)
((and (eq (car form) 'FUNCTION)
(case (second form)
(CALL-NEXT-METHOD
(setq call-next-method-p 'T
closurep 'T
save-original-args 'T)
form)
(NEXT-METHOD-P
(setq next-method-p-p 'T)
form)
(t nil))))
((and (eq (car form) 'SLOT-VALUE)
(symbolp (second form))
(constantp (third form)))
(multiple-value-bind (ignore class)
(can-optimize-access (second form) env)
(if class
(optimize-slot-value class form)
form)))
;; does not work for (push x (slot-value y 's))
;; and similia, since push is turned into
;; (|(setf slot-value)| (cons (slot-value y 's) x) x 's)
((eq (car form) 'SETF)
(if (cdddr form)
(do* ((setf-list (cdr form) (cddr setf-list))
(instance-access)
(value)
(result))
((null setf-list)
(cons 'PROGN (nreverse result)))
(setq instance-access (car setf-list)
value (second setf-list))
(push
(if (and instance-access
(listp instance-access)
(eq (car instance-access)
'SLOT-VALUE)
(symbolp (second instance-access))
(constantp (third instance-access)))
(multiple-value-bind (ignore class)
(can-optimize-access
(second instance-access) env)
(let ((new-form
(list 'SETF instance-access
value)))
(if class
(optimize-set-slot-value class
new-form)
new-form)))
(list 'SETF instance-access value))
result))
(if (and (cdr form)
(second form)
(listp (second form))
(eq (caadr form) 'SLOT-VALUE)
(symbolp (cadadr form))
(constantp (third (second form))))
(multiple-value-bind (ignore class)
(can-optimize-access (cadadr form) env)
(if class
(optimize-set-slot-value class form)
form))
form)))
((eq (car form) 'STANDARD-INSTANCE-ACCESS)
(multiple-value-bind (parameter class)
(can-optimize-access (second form) env)
(if class
(optimize-standard-instance-access
class parameter form slots)
form)))
(t form))))
(values (walk-form method-lambda env #'walk-function)
(if closurep 'FUNCTION call-next-method-p)
save-original-args
next-method-p-p))))
(defun add-lexical-functions-to-method-lambda (walked-declarations
walked-lambda-body
generic-function-name
walked-lambda
original-args
lambda-list
save-original-args
applyp
aux-bindings
call-next-method-p
next-method-p-p)
(declare (si::c-local))
;;
;; WARNING: these &rest/apply combinations produce useless garbage. Beppe
;;
(cond ((and (null save-original-args)
(null applyp))
;;
;; We don't have to save the original arguments. In addition,
;; this method doesn't take any &mumble arguments (this means
;; that there is no way the lexical functions can be used inside
;; of the default value form for an &mumble argument).
;;
;; We can expand this into a simple lambda expression with an
;; FLET to define the lexical functions.
;;
`(ext::lambda-block ,generic-function-name ,lambda-list
,@walked-declarations
(let* ((.next-method. (car *next-methods*))
(*next-methods* (cdr *next-methods*)))
(flet (,@(and call-next-method-p
'((CALL-NEXT-METHOD (&REST CNM-ARGS)
;; (declare (static-extent cnm-args))
(IF .NEXT-METHOD.
(APPLY .NEXT-METHOD. CNM-ARGS)
(ERROR "No next method.")))))
,@(and next-method-p-p
'((NEXT-METHOD-P ()
(NOT (NULL .NEXT-METHOD.))))))
,@walked-lambda-body)))
;; Assuming that we can determine statically which is the next method,
;; we could use this solution. Compute-effective-method can set
;; the value of .next-method. within each closure at the appropriate
;; value. Same thing for next case. Beppe
;; `(let (.next-method.)
;; (lambda ,lambda-list
;; ,@walked-declarations
;; (flet (,@(and call-next-method-p
;; '((CALL-NEXT-METHOD (&REST CNM-ARGS)
;; ;; (declare (static-extent cnm-args))
;; (IF .NEXT-METHOD.
;; (APPLY .NEXT-METHOD. CNM-ARGS)
;; (ERROR "No next method.")))))
;; ,@(and next-method-p-p
;; '((NEXT-METHOD-P ()
;; (NOT (NULL .NEXT-METHOD.))))))
;; ,@walked-lambda-body)))
)
((null applyp)
;;
;; This method doesn't accept any &mumble arguments. But we
;; do have to save the original arguments (this is because
;; call-next-method is being called with no arguments).
;; Have to be careful though, there may be multiple calls to
;; call-next-method, all we know is that at least one of them
;; is with no arguments.
;;
`(ext::lambda-block ,generic-function-name ,original-args
(let* ((.next-method. (car *next-methods*))
(*next-methods* (cdr *next-methods*)))
(flet (,@(and call-next-method-p
`((call-next-method (&rest cnm-args)
;; (declare (static-extent cnm-args))
(if .next-method.
(if cnm-args
(apply .next-method. cnm-args)
(funcall .next-method. ,@original-args))
(error "No next method.")))))
,@(and next-method-p-p
'((NEXT-METHOD-P ()
(NOT (NULL .NEXT-METHOD.))))))
(let* (,@(mapcar #'list
(subseq lambda-list 0
(position '&AUX lambda-list))
original-args)
,@aux-bindings)
,@walked-declarations
,@walked-lambda-body)))))
(t
;;
;; This is the fully general case.
;; We must allow for the lexical functions being used inside
;; the default value forms of &mumble arguments, and if must
;; allow for call-next-method being called with no arguments.
;;
`(lambda ,original-args
(let* ((.next-method. (car *next-methods*))
(*next-methods* (cdr *next-methods*)))
(flet (,@(and call-next-method-p
`((call-next-method (&rest cnm-args)
;; (declare (static-extent cnm-args))
(if .next-method.
(if cnm-args
(apply .next-method. cnm-args)
(apply .next-method.
,@(remove '&REST original-args)))
(error "No next method.")))))
,@(and next-method-p-p
'((NEXT-METHOD-P ()
(NOT (NULL .NEXT-METHOD.))))))
(apply (function ,walked-lambda)
,@(remove '&REST original-args))))))))
;;; ----------------------------------------------------------------------
;;; parsing
(defun legal-generic-function-name-p (name)
(si::valid-function-name-p name))
(defun parse-defmethod (args)
(declare (si::c-local))
;; This function has to extract the name of the method, a list of
;; possible qualifiers (identified by not being lists), the lambda
;; list of the method (which might be empty!) and the body of the
;; function.
(let* (name)
(unless args
(error "Illegal defmethod form: missing method name"))
(setq name (pop args))
(unless (legal-generic-function-name-p name)
(error "~A cannot be a generic function specifier.~%~
It must be either a non-nil symbol or ~%~
a list whose car is setf and whose second is a non-nil symbol."
name))
(do ((qualifiers '()))
((progn
(when (endp args)
(error "Illegal defmethod form: missing lambda-list"))
(listp (first args)))
(values name (nreverse qualifiers) (first args) (rest args)))
(push (pop args) qualifiers))))
(defun parse-specialized-lambda-list (arglist warningp)
(declare (si::c-local))
;; This function has been modified to get an easy control on the
;; correctness of the specialized-lambda-list. Furthermore it has became
;; an iterative function.
;; -- Daniele --
(let* (parameters lambda-list specializers)
(do ((arg (first arglist) (first arglist)))
((or (null arglist)
(member arg '(&OPTIONAL &REST &KEY &ALLOW-OTHER-KEYS &AUX))))
(pop arglist)
(when (and warningp (member arg lambda-list-keywords))
(warn "Unrecognized lambda-list keyword ~S in arglist.~%~
Assume this keyword as a required parameter."
arg))
(push (if (listp arg) (first arg) arg) parameters)
(push (if (listp arg) (first arg) arg) lambda-list)
(push (if (listp arg) (if (consp (second arg))
`(eql ,(eval (cadadr arg)))
(second arg))
())
specializers))
(when (eq (first arglist) '&OPTIONAL)
(push (pop arglist) lambda-list)
(do ((arg (first arglist) (first arglist)))
((or (null arglist)
(member arg '(&OPTIONAL &REST &KEY &ALLOW-OTHER-KEYS
&AUX))))
(pop arglist)
(when (and warningp (member arg lambda-list-keywords))
(warn "Unrecognized lambda-list keyword ~S in arglist.~%~
Assume this keyword as an optional parameter."
arg))
(push (if (listp arg) (first arg) arg) parameters)
(push arg lambda-list)))
(when (eq (first arglist) '&REST)
(push (pop arglist) lambda-list)
(when (not (symbolp (first arglist)))
(error "~S in the lambda-list is not a symbol."
(first arglist)))
(push (pop arglist) lambda-list))
(when (eq (first arglist) '&KEY)
(push (pop arglist) lambda-list)
(do ((arg (first arglist) (first arglist)))
((or (null arglist)
(member arg '(&OPTIONAL &REST &KEY &AUX))))
(pop arglist)
(when (eq arg '&ALLOW-OTHER-KEYS)
(push arg lambda-list)
(return))
(when (and warningp (member arg lambda-list-keywords))
(warn "Unrecognized lambda-list keyword ~S in arglist.~%~
Assume this keyword as a keyword parameter."
arg))
(push (if (listp arg) (first arg) arg) parameters)
(push arg lambda-list)))
(when (eq (first arglist) '&AUX)
(push (pop arglist) lambda-list)
(do ((arg (first arglist) (first arglist)))
((or (null arglist)
(member arg '(&OPTIONAL &REST &KEY &ALLOW-OTHER-KEYS
&AUX))))
(pop arglist)
(when (and warningp (member arg lambda-list-keywords))
(warn "Unrecognized lambda-list keyword ~S in arglist.~%~
Assume this keyword as an aux parameter."
arg))
(push (if (listp arg) (first arg) arg) parameters)
(push arg lambda-list)))
(when arglist (error "The position of the lambda-list keyword ~S~%~
is not correct."
(first arglist)))
(values (nreverse parameters)
(nreverse lambda-list)
(nreverse specializers))))
(defun declaration-specializers (arglist declarations)
(declare (si::c-local))
(do ((argscan arglist (cdr argscan))
(declist (when declarations (cdr declarations))))
((or
(null argscan)
(member (first argscan) '(&OPTIONAL &REST &KEY &ALLOW-OTHER-KEYS &AUX)))
`(DECLARE ,@declist))
(when (listp (first argscan))
(push `(TYPE ,(cadar argscan) ,(caar argscan)) declist))))
;;; ----------------------------------------------------------------------
;;; operations
(defun make-method (qualifiers specializers lambda-list
fun plist options gf method-class)
(let ((method (si:allocate-raw-instance nil (find-class 'standard-method nil)
#.(length +standard-method-slots+))))
(setf (method-generic-function method) nil
(method-lambda-list method) lambda-list
(method-function method) fun
(method-specializers method) specializers
(method-qualifiers method) qualifiers
(method-plist method) plist)
method))
;;; early version used during bootstrap
(defun method-p (x)
(si::instancep x))
(defun method-needs-next-methods-p (method)
(getf (method-plist method) :needs-next-methods-p))
;;; early version used during bootstrap
(defun add-method (gf method)
(let* ((name (generic-function-name gf))
(method-entry (assoc name *early-methods*)))
(unless method-entry
(setq method-entry (list name))
(push method-entry *early-methods*))
(push method (cdr method-entry))
(push method (generic-function-methods gf))
(setf (method-generic-function method) gf)
(unless (si::sl-boundp (generic-function-lambda-list gf))
(setf (generic-function-lambda-list gf) (method-lambda-list method))
(setf (generic-function-argument-precedence-order gf)
(rest (si::process-lambda-list (method-lambda-list method) t))))
(compute-g-f-spec-list gf)
method))
(defun find-method (gf qualifiers specializers &optional (errorp t))
(declare (notinline method-qualifiers))
(let* ((method-list (generic-function-methods gf))
(required-args (subseq (generic-function-lambda-list gf) 0
(length specializers)))
found)
(dolist (method method-list)
(when (and (equal qualifiers (method-qualifiers method))
(equal specializers (method-specializers method)))
(return-from find-method method)))
;; If we did not find any matching method, then the list of
;; specializers might have the wrong size and we must signal
;; an error.
(cond ((/= (length specializers)
(length (generic-function-argument-precedence-order gf)))
(error
"The specializers list~%~A~%does not match the number of required arguments in ~A"
specializers (generic-function-name gf)))
(errorp
(error "There is no method on the generic function ~S that agrees on qualifiers ~S and specializers ~S"
(generic-function-name gf)
qualifiers specializers)))
nil))
;;; ----------------------------------------------------------------------
;;; with-slots
(defmacro with-slots (slot-entries instance-form &body body)
(let* ((temp (gensym))
(accessors
(do ((scan slot-entries (cdr scan))
(res))
((null scan) (nreverse res))
(if (symbolp (first scan))
(push `(,(first scan) (slot-value ,temp ',(first scan))) res)
(push `(,(caar scan)
(slot-value ,temp ',(cadar scan))) res)))))
`(let ((,temp ,instance-form))
(symbol-macrolet ,accessors ,@body))))
;(with-slots (x (y2 y)) inst (setq x y2))
;;; ----------------------------------------------------------------------
;;; with-accessors
(defmacro with-accessors (slot-accessor-pairs instance-form &body body)
(let* ((temp (gensym))
(accessors (do ((scan slot-accessor-pairs (cdr scan))
(res))
((null scan) (nreverse res))
(push `(,(caar scan) (,(cadar scan) ,temp)) res))))
`(let ((,temp ,instance-form))
(symbol-macrolet ,accessors ,@body))))
;;; ----------------------------------------------------------------------
;;; optimizers
(defun can-optimize-access (var env)
(declare (si::c-local))
;; (values required-parameter class)
(let ((required-parameter?
(or (third (variable-declaration 'VARIABLE-REBINDING var env))
var)))
(if required-parameter?
(values required-parameter?
(find-class (variable-class required-parameter? env) 'NIL))
(values nil nil))))
(defun optimize-standard-instance-access (class parameter form slots)
(declare (si::c-local))
;; Returns an optimized form corresponding to FORM.
;; SLOTS is a list of:
;; (parameter [(class . class-index-table) {(slot-name . slot-index)}+])
;; parameters of the same class share the cdr of such list.
;;
(let* ((instance (second form))
(slot-name (reduce-constant (third form)))
(new (fourth form))
(entry (assoc parameter slots :test #'eq))
slot)
(unless entry
(error "Can't optimize instance access. Report this as a bug."))
(setq slot (find slot-name (slot-value class 'SLOTS)
:key #'slot-definition-name))
(if (and slot (eq :INSTANCE (slot-definition-allocation slot)))
(let* (slot-entry slot-index)
(unless (cdr entry)
;; there is just one index-table for each different class
(let ((class-slot-info (find class slots :key #'caadr :test #'eq)))
(setf (cdr entry)
(if class-slot-info
(cdr class-slot-info)
;; create variable for index-table
(list (cons class (gensym)))))))
(setq slot-entry (assoc slot-name (cddr entry) :test #'eq))
(if slot-entry
(setq slot-index (cdr slot-entry))
(push (cons slot-name (setq slot-index (gensym)))
(cddr entry)))
(if new
`(si:instance-set ,instance ,slot-index ,new)
`(the ,(slot-definition-type slot)
(si:instance-ref-safe ,instance ,slot-index))))
;; dont'optimize shared slots
(if new
`(standard-instance-set ,new ,instance ',slot-name)
`(standard-instance-get ,instance ',slot-name)))))
;(defun get-slot-definition-type (class slot)
; (slot-definition-type (find slot (slot-value class 'SLOTS) :key #'slot-definition-name)))
(defun signal-slot-unbound (instance slot-name)
(declare (si::c-local))
(slot-unbound (si:instance-class instance) instance slot-name))
(defun add-index-binding (method-body isl)
(declare (si::c-local))
(let* (class-index-bindings
slot-index-bindings
slot-index-declarations)
;; don't forget setf! Chicca
(setf class-index-bindings
(dolist (entry isl (nreverse class-index-bindings))
;; check if the entry provides the information needed! Chicca
(when (cdr entry)
(unless (assoc (cdadr entry) class-index-bindings :test #'eq)
(push `(,(cdadr entry)
(let ((class (si:instance-class ,(first entry))))
(declare (type standard-class class))
(slot-index-table class)))
class-index-bindings)))))
;; don't forget setf! Chicca
(setf slot-index-bindings
(dolist (entry isl (nreverse slot-index-bindings))
(dolist (slot-entry (cddr entry))
(push `(,(cdr slot-entry)
(slot-index ',(first slot-entry) ,(cdadr entry)))
slot-index-bindings)
(push `(fixnum ,(cdr slot-entry))
slot-index-declarations))))
`((let ,class-index-bindings
(let ,slot-index-bindings
(declare . ,slot-index-declarations)
. ,method-body)))))
;;; Force the compiler into optimizing use of gethash inside methods:
(setf (symbol-function 'SLOT-INDEX) (symbol-function 'GETHASH))
(put-sysprop 'SLOT-INDEX ':INLINE-ALWAYS
'(((T T) FIXNUM NIL NIL "fix(gethash(#0,#1))")
((T T) T NIL NIL "gethash_safe(#0,#1,Cnil)")))
(defun reduce-constant (old)
(let ((new (eval old)))
(if (eq new old)
new
(if (constantp new)
(reduce-constant new)
new))))
;;; ----------------------------------------------------------------------
;;; walker
;;; Inform the walker of the kind of declarations to consider:
(pushnew 'TYPE *variable-declarations*)
(pushnew 'VARIABLE-REBINDING *variable-declarations*)
(defun variable-class (var env)
(second (variable-declaration 'TYPE var env)))
;;; ----------------------------------------------------------------------