assertion failures - providing feedback

What is the intended way to provide feedback when an assertion fails?

Given:

<xs:assert test="@min le @max"/>

How would you say "The min attribute must be less than or equal to the
max attribute" when the test fails?

I hope it's not:

<xs:assert test="if (@min le @max) then true() else
error('http://mycomp.com', 'myerr:minlessthanmax', 'The min attribute
must be less than or equal to the max attribute')"/>



thanks
-- 
Andrew Welch
http://andrewjwelch.com
Kernow: http://kernowforsaxon.sf.net/