Out-of-range subsequences

[Daniels.pa@Xerox.COM]

Is it an error for a subsequence description to index elements that are
"off the end" of a sequence? By analogy with ELT, it should be, but I
have seen a couple of implementations that quietly take the intersection
of the intervals and go on from there? This would be true for SUBSEQ as
well as any sequence function that allows :START and :END keywords.

In particular, is (subseq #(1 2 3) 0 5) an error? 

		-- Andy. --