+ (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))