> Oh. Well that's a bad decision, as you no longer have the neat divide
> between exact arithmetic (requested by xs:integer or xs:decimal) and
> inexact arithmetic (requested by xs:double and xs:float) that you get
> in XML Schema.

XML schema doesn't guarantee exact arithmetic for integer or decimal
either 

http://www.w3.org/TR/xmlschema-2/#decimal

says


Note:  All 7minimally conforming7 processors 7must7 support
decimal numbers with a minimum of 18 decimal digits (i.e., with a
7totalDigits7 of 18). However, 7minimally conforming7
processors 7may7 set an application-defined limit on the maximum
number of decimal digits they are prepared to support, in which case
that application-defined maximum number 7must7 be clearly
documented.  

and xs:integer is derived from xs::decimal so also not guaranteed to be
exact.

David

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