(let ((predicate-name (second hairy-spec)))
(declare (type symbol predicate-name)) ; by ANSI spec of SATISFIES
(if (fboundp predicate-name)
- (values (not (null (funcall predicate-name obj))) t)
+ (let* (;; "Is OBJ of the SATISFIES type?" represented
+ ;; as a generalized boolean.
+ ;;
+ ;; (Why IGNORE-ERRORS? This code is used to try to
+ ;; check type relationships at compile time.
+ ;; Passing only-slightly-twisted types like
+ ;; (AND INTEGER (SATISFIES ODDP)) into the
+ ;; rather-significantly-twisted type dispatch
+ ;; system can easily give rise to oddities like
+ ;; calling predicates like ODDP on values they
+ ;; don't like. (E.g. on OBJ=#\NEWLINE when the
+ ;; above type is tested for TYPE= against
+ ;; STANDARD-CHAR, represented as a
+ ;; MEMBER-TYPE.) In such cases, NIL seems to be
+ ;; an appropriate answer to "is OBJ of the
+ ;; SATISFIES type?")
+ (gbool (ignore-errors (funcall predicate-name obj)))
+ ;; RAW coerced to a pure BOOLEAN value
+ (bool (not (not gbool))))
+ (values bool t))
(values nil nil)))))))))
\f
;;; Return the layout for an object. This is the basic operation for
csubtypep-cache-clear
type-intersection2-cache-clear
values-type-intersection-cache-clear))
- (funcall (symbol-function sym))))
+ (funcall (the function (symbol-function sym)))))
(values))
-;;; Like TYPE-OF, only we return a CTYPE structure instead of a type
-;;; specifier, and we try to return the type most useful for type
-;;; checking, rather than trying to come up with the one that the user
-;;; might find most informative.
+;;; This is like TYPE-OF, only we return a CTYPE structure instead of
+;;; a type specifier, and we try to return the type most useful for
+;;; type checking, rather than trying to come up with the one that the
+;;; user might find most informative.
(declaim (ftype (function (t) ctype) ctype-of))
(defun-cached (ctype-of
:hash-function (lambda (x) (logand (sxhash x) #x1FF))