Re: datatyping discussion

Sergey Melnik wrote:

[...]


>>Hmmm, what do we mean by type here?  Are 'Pounds' a type?  Methinks the type is
>>either integer or float.  Pounds are a unit.


I agree we have to understand how to do both.  My intuitions are that units and 
types are orthogonal things.

[...]


> 
> Well, the XSD spec distinguishes between "value spaces" and "lexical
> spaces". Thus, "decimal" has got both. In fact, I'm thinking hard
> whether it makes sense to make this distinction explicit, so that value
> spaces and lexical spaces may be defined independently. For example, it
> may make sense to speak of a value space of say Java integer
> [-2147483648..214783647] vs. a lexical space of integers that can be
> represented using a hexadecimal string of a certain length. As another
> example, consider two disjoint lexical spaces for decimals: one in which
> each lexical token has exactly one digit before the dot (e.g. "1.23E1")
> vs. the other one in which use of "E" is prohibited (e.g. "12.3"). These
> two lexical spaces are disjoint and can both be used alternatively to
> encode decimals.


Again I agree :).  Lexical spaces and value spaces are different things.

Brian