Re: intersecting schema with application-specific validation

["Thomas B. Passin" <tpassin@home.com>]

This was discussed on this list a month or two ago.  Schematron might be a
good choice for validating things  that xml-schema cannot.  Or maybe RELAX
or TREX.

[sabba]

I'm happy that w3c schema have right yesterday (2nd may '01) become a
reccomendation,
still i think i won't be able to express all validations i need to express
using just an xml schema, moreover i need to generate a "new instance" based
on this "schema" , and so i'll need to put more info "somewhere" since an
xmlschema leaves you, evidently,  too much freedom in this "new instance"
process.
The point where my doubts are is that , since schema won't be enough , where
should i put extra "application specific" validation info (a custom xml
syntax ?) . how can i apply both validations in a consistent manner that
won't lead to spaghetti code.
if there is any standard, approach , best practice you are aware ? i'd like
to know.
thank in advance.