Datatype test cases/ datatype entailment/ datatype support.

The cross-datatype entailment test cases are reasonably clear cut, from
a mathematical point of view, I think. But Patrick raises a good point
when he asks (with a weather eye on implementation?) "what does it mean
to say that datatype X is supported?"


The intention with an entailment test case that's described as having
datatype support for DTs X, Y and Z is this: that to be able to run the
test case, you are able to decide:

	for any two datatyped literals, a and b, with the datatypes
	of a and b coming from {X, Y, Z},

	do a and b represent the same value?

(You don't need to be able to work out what that value is; just to
answer that question.)


Now, it might be better if the "datatype support" was recorded in the
test case manifest using a cons list; I'm willing to take advice on
that, but that is what is meant by the manifest contents at this stage.

jan

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jan grant, ILRT, University of Bristol. http://www.ilrt.bris.ac.uk/
Tel +44(0)117 9287088 Fax +44 (0)117 9287112 http://ioctl.org/jan/
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