implémentation de sbcl :

; in: LAMBDA (#:WHOLE2122 #:ENVIRONMENT2123)
;     (LET* ((OBJECT (CAR (CDR #:WHOLE2122)))
;            (BODY (CAR (CDR #)))
;            (CATCH-CODE (CAR (CDR #))))
;       (BLOCK TAGBODY-UNWIND-CATCH CATCH-CODE `(TAGBODY ,@(CDR BODY))))