Date: Mon, 9 Jan 89 21:42 EST From: Robert W. Kerns <RWK@F.ILA.Dialnet.Symbolics.COM> OK, next question: Does it open-code or otherwise optimize TYPEP, or just call TYPEP on the list? KCL just calls TYPEP on the list. One of the patches that I have made to KCL is a version of TYPEP that open-codes when the type is a constant, but my patch has the bug. Richard Harris