Issue: SUBTYPEP-EMPTY-NIL (Version 1)

[Kent M Pitman <KMP@STONY-BROOK.SCRC.Symbolics.COM>]

    Date: 8 Feb 89 14:02:52 EST (Wed)
    From: gz@spt.entity.com (Gail Zacharias)

       If CLtL is clear and I've just missed the passage, by all means cite it.  

    CLtL p72: "If a data type is viewed as the set of all objects belonging to the
    type, then the TYPEP function is a set membership test, while SUBTYPEP is a
    subset test."

Hmmm. I'd missed that little paragraph up there. It does seem to support
your claim (though it still makes me a little queasy). The wording is
obviously informal since I might just as easily expect the term "subset
test" to imply something like (subtypep '(3 4 5) 'number) => t, but
later examples seem to fix that up ok.  Also, whenever very informal
descriptions like this occur, I'm a bit leary of drawing too many
conclusions from them because I'm not certain that the speaker 
(Steele in this case) had intended the wording to hold up under too
much heavy inferencing...

Still, if no one disagrees that this is the apparent intent (and no one but me
has spoken up so far), then I'm content to declare this issue resolved by sending
mail to Kathy identifying the issue, and asking her to resolve it by making
the point clearer [per option T-T, which permits results T T or NIL NIL] and
including the examples from the writeup. The simple presence of those examples
in the draft to be approved will make it apparent to reviewers that we believe
this to be a consequence of the wording, and that if they disagree they should
object [as they would object to anything else that they noticed to be 
incongruous].