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Out-of-range subsequences

    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? 

I don't see any clear statement in the book about this, but in my
opinion this should "be an error" and should probably be required to
signal an error.

-- Scott