(/show0 "failing in MUST-SUPPLY-THIS")
(error "missing type method for ~S" foo))
-;;; A TYPE-CLASS object represents the "kind" of a type. It mainly contains
-;;; functions which are methods on that kind of type, but is also used in EQ
-;;; comparisons to determined if two types have the "same kind".
+;;; A TYPE-CLASS object represents the "kind" of a type. It mainly
+;;; contains functions which are methods on that kind of type, but is
+;;; also used in EQ comparisons to determined if two types have the
+;;; "same kind".
(def!struct (type-class
#-no-ansi-print-object
(:print-object (lambda (x stream)
(simple-subtypep #'must-supply-this :type function)
(complex-subtypep-arg1 nil :type (or function null))
(complex-subtypep-arg2 nil :type (or function null))
- ;; SIMPLE-UNION combines two types of the same class into a single
- ;; type of that class. If the result is a two-type union, then
- ;; return NIL. VANILLA-UNION returns whichever argument is a
- ;; supertype of the other, or NIL.
- (simple-union #'vanilla-union :type function)
- (complex-union nil :type (or function null))
- ;; The default intersection methods assume that if one type is a
- ;; subtype of the other, then that type is the intersection.
- (simple-intersection #'vanilla-intersection :type function)
- (complex-intersection nil :type (or function null))
+ ;; SIMPLE-UNION2, COMPLEX-UNION2, SIMPLE-INTERSECTION2, and
+ ;; COMPLEX-INTERSECTION2 methods take pairs of types and try to find
+ ;; a new type which expresses the result nicely, better than could
+ ;; be done by just stuffing the two component types into an
+ ;; UNION-TYPE or INTERSECTION-TYPE object. They return NIL on
+ ;; failure, or a CTYPE for success.
+ ;;
+ ;; Note: These methods are similar to CMU CL's SIMPLE-UNION,
+ ;; COMPLEX-UNION, SIMPLE-INTERSECTION, and COMPLEX-UNION methods.
+ ;; They were reworked in SBCL because SBCL has INTERSECTION-TYPE
+ ;; objects (where CMU CL just punted to HAIRY-TYPE) and because SBCL
+ ;; wants to simplify unions and intersections by considering all
+ ;; possible pairwise simplifications (where the CMU CL code only
+ ;; considered simplifications between types which happened to appear
+ ;; next to each other the argument sequence).
+ ;;
+ ;; Differences in detail from old CMU CL methods:
+ ;; * SBCL's methods are more parallel between union and
+ ;; intersection forms. Each returns one values, (OR NULL CTYPE).
+ ;; * SBCL doesn't use type methods to deal with unions or
+ ;; intersections of the COMPOUND-TYPE of the corresponding form.
+ ;; Instead the wrapper functions TYPE-UNION2, TYPE-INTERSECTION2,
+ ;; TYPE-UNION, and TYPE-INTERSECTION handle those cases specially
+ ;; (and deal with canonicalization/simplification issues at the
+ ;; same time).
+ (simple-union2 #'hierarchical-union2 :type function)
+ (complex-union2 nil :type (or function null))
+ (simple-intersection2 #'hierarchical-intersection2 :type function)
+ (complex-intersection2 nil :type (or function null))
(simple-= #'must-supply-this :type function)
(complex-= nil :type (or function null))
;; a function which returns a Common Lisp type specifier
)
(eval-when (:compile-toplevel :load-toplevel :execute)
+ ;; KLUDGE: If the slots of TYPE-CLASS ever change, the slots here
+ ;; will have to be tweaked to match. -- WHN 19991021
+ (defparameter *type-class-function-slots*
+ '((:simple-subtypep . type-class-simple-subtypep)
+ (:complex-subtypep-arg1 . type-class-complex-subtypep-arg1)
+ (:complex-subtypep-arg2 . type-class-complex-subtypep-arg2)
+ (:simple-union2 . type-class-simple-union2)
+ (:complex-union2 . type-class-complex-union2)
+ (:simple-intersection2 . type-class-simple-intersection2)
+ (:complex-intersection2 . type-class-complex-intersection2)
+ (:simple-= . type-class-simple-=)
+ (:complex-= . type-class-complex-=)
+ (:unparse . type-class-unparse))))
-;;; Copy TYPE-CLASS object X, using only operations which will work early in
-;;; cold load. (COPY-STRUCTURE won't work early in cold load, because it needs
-;;; RAW-INDEX and RAW-LENGTH information from LAYOUT-INFO, and LAYOUT-INFO
-;;; isn't initialized early in cold load.)
+(eval-when (:compile-toplevel :load-toplevel :execute)
+
+;;; Copy TYPE-CLASS object X, using only operations which will work
+;;; early in cold load. (COPY-STRUCTURE won't work early in cold load,
+;;; because it needs RAW-INDEX and RAW-LENGTH information from
+;;; LAYOUT-INFO, and LAYOUT-INFO isn't initialized early in cold
+;;; load.)
;;;
-;;; FIXME: It's nasty having to maintain this hand-written copy function. And
-;;; it seems intrinsically dain-bramaged to have RAW-INDEX and RAW-LENGTH in
-;;; LAYOUT-INFO instead of directly in LAYOUT. We should fix this: * Move
-;;; RAW-INDEX and RAW-LENGTH slots into LAYOUT itself. * Rewrite the various
-;;; CHECK-LAYOUT-related functions so that they check RAW-INDEX and RAW-LENGTH
-;;; too. * Remove this special hacked copy function, just use COPY-STRUCTURE
-;;; instead. (For even more improvement, it'd be good to move the raw slots
+;;; FIXME: It's nasty having to maintain this hand-written copy
+;;; function. And it seems intrinsically dain-bramaged to have
+;;; RAW-INDEX and RAW-LENGTH in LAYOUT-INFO instead of directly in
+;;; LAYOUT. We should fix this:
+;;; * Move RAW-INDEX and RAW-LENGTH slots into LAYOUT itself.
+;;; * Rewrite the various CHECK-LAYOUT-related functions so that
+;;; they check RAW-INDEX and RAW-LENGTH too.
+;;; * Remove this special hacked copy function, just use
+;;; COPY-STRUCTURE instead.
+;;; (For even more improvement, it might be good to move the raw slots
;;; into the same object as the ordinary slots, instead of having the
-;;; unfortunate extra level of indirection. But that'd probably require a lot
-;;; of work, including updating the garbage collector to understand it.)
+;;; unfortunate extra level of indirection. But that'd probably
+;;; require a lot of work, including updating the garbage collector to
+;;; understand it. And it might even hurt overall performance, because
+;;; the positive effect of removing indirection could be cancelled by
+;;; the negative effect of imposing an unnecessary GC write barrier on
+;;; raw data which doesn't actually affect GC.)
(declaim (ftype (function (type-class) type-class) copy-type-class-coldly))
(defun copy-type-class-coldly (x)
- ;; KLUDGE: If the slots of TYPE-CLASS ever change, the slots here will have
- ;; to be hand-tweaked to match. -- WHN 19991021
- (make-type-class :name (type-class-name x)
- :simple-subtypep (type-class-simple-subtypep x)
- :complex-subtypep-arg1 (type-class-complex-subtypep-arg1 x)
- :complex-subtypep-arg2 (type-class-complex-subtypep-arg2 x)
- :simple-union (type-class-simple-union x)
- :complex-union (type-class-complex-union x)
- :simple-intersection (type-class-simple-intersection x)
- :complex-intersection (type-class-complex-intersection x)
- :simple-= (type-class-simple-= x)
- :complex-= (type-class-complex-= x)
- :unparse (type-class-unparse x)))
-
-;;; KLUDGE: If the slots of TYPE-CLASS ever change, the slots here
-;;; will have to be tweaked to match. -- WHN 19991021
-(defparameter *type-class-function-slots*
- '((:simple-subtypep . type-class-simple-subtypep)
- (:complex-subtypep-arg1 . type-class-complex-subtypep-arg1)
- (:complex-subtypep-arg2 . type-class-complex-subtypep-arg2)
- (:simple-union . type-class-simple-union)
- (:complex-union . type-class-complex-union)
- (:simple-intersection . type-class-simple-intersection)
- (:complex-intersection . type-class-complex-intersection)
- (:simple-= . type-class-simple-=)
- (:complex-= . type-class-complex-=)
- (:unparse . type-class-unparse)))
+ ;; KLUDGE: If the slots of TYPE-CLASS ever change in a way not
+ ;; reflected in *TYPE-CLASS-FUNCTION-SLOTS*, the slots here will
+ ;; have to be hand-tweaked to match. -- WHN 2001-03-19
+ (make-type-class :name (type-class-name x)
+ . #.(mapcan (lambda (type-class-function-slot)
+ (destructuring-bind (keyword . slot-accessor)
+ type-class-function-slot
+ `(,keyword (,slot-accessor x))))
+ *type-class-function-slots*)))
(defun class-function-slot-or-lose (name)
(or (cdr (assoc name *type-class-function-slots*))
) ; EVAL-WHEN
(defmacro !define-type-method ((class method &rest more-methods)
- lambda-list &body body)
- (let ((name (symbolicate CLASS "-" method "-TYPE-METHOD")))
+ lambda-list &body body)
+ (let ((name (symbolicate class "-" method "-TYPE-METHOD")))
`(progn
(defun ,name ,lambda-list
,@body)
;;; complex method. If there isn't a distinct COMPLEX-ARG1 method,
;;; then swap the arguments when calling TYPE1's method. If no
;;; applicable method, return DEFAULT.
+;;;
+;;; KLUDGE: It might be a lot easier to understand this and the rest
+;;; of the type system code if we used CLOS to express it instead of
+;;; trying to maintain this squirrely hand-crufted object system.
+;;; Unfortunately that'd require reworking PCL bootstrapping so that
+;;; all the compilation can get done by the cross-compiler, which I
+;;; suspect is hard, so we'll bear with the old system for the time
+;;; being. -- WHN 2001-03-11
(defmacro !invoke-type-method (simple complex-arg2 type1 type2 &key
(default '(values nil t))
(complex-arg1 :foo complex-arg1-p))