The philosophy of Nothing
pbenedict at apache.org
Sun Nov 29 13:06:06 PST 2009
Neal, can clarify this:
> There are no elements of the type Nothing. Therefore all of the elements
> of the type Nothing are elements of the type T, for every T.
The first statement says there are no elements, but the second says
there are elements.
On Sun, Nov 29, 2009 at 2:57 PM, Neal Gafter <neal at gafter.com> wrote:
> On Sun, Nov 29, 2009 at 12:33 PM, Paul Benedict <pbenedict at apache.org>
>> Yes, I do have it flipped around. Thank you. I shouldn't enjoy making
>> big blunders in public so much. :-)
>> So let me ask the opposite:
>> How can nothing be a type of something?
> A type T is a subtype of a type S iff all of the elements of the type T are
> elements of the type S.
> For example, String is a subtype of Object because all of the elements of
> the type String are elements of the type Object.
> There are no elements of the type Nothing. Therefore all of the elements of
> the type Nothing are elements of the type T, for every T. Therefore Nothing
> is a subtype of the type T, for every T.
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