RE: Types and Context

[Gavin Thomas Nicol <gtn@ebt.com>]

> Ah, but this obscures a distinction that is fundamental.  It is one
> thing to *use* the counterparty data to establish the settlement price,
> and it is quite another thing to *interpret* the counterparty data
> *as* the settlement price.

If I choose to do so, so be it. Local interpretation is everything...
and interoperability only occurs because I choose to adhere to the
protocol/intent of the protocol. 

In other words, XML guarantess interoperability only to the degree
that the parties involved adhere to the protocol the markup defines
(ie. to the degree they both agree what things mean). There is
nothing intrinsic about the data that *guarantees* such interpretation.

You can build systems that are secure in that processes are
are constrained in the number of ways they can interpret data (essentially
by forcing an interpretation by supplying the local interpreter). These
systems are hard to design and build though... and are generally
closed systems.