From: Steve Bacher (C.S.Draper Lab) To: common-lisp <common-lisp at SU-AI> Subject: subseq How about (subseq #(1 2 3) 0 5 :signal-error nil) ? This seems ideal to me, since the programmer's intention (i.e. whether or not an out-of-bounds condition is expected) is stated right there in the function call form.