Problem with attribute parsing?

Hello I was doing some experiments and I ended up with this:

let $c := <Class Source='{ttt'></Class>
return $c/@Source

When this is compiled in the BaseX GUI app, an error message ensues: Error: Stopped at ... /file3, 1/30: [XPST0003] Expecting '}', found '''. Query: let $c := <Class Source='{ttt'></Class> return $c/@Source Query plan: <QueryPlan compiled="false" updating="false"/> Surely that is not correct? If I add a } there, everything is fine:

let $c := <Class Source='{ttt}'></Class>
return $c/@Source

I don't think there is an XML requirement forcing escaping start brace ('{') inside an attribute value? I know that XQuery supports <X A='{...}' /> where the inside of the {} is evaluated to give the value for the A attribute, but the example above is not XQuery, just an XML literal. I am sure I would have noticed this if it were a general problem. Best Regards Peter Villadsen Principal Architect Microsoft Business Applications Group

This is an error because the braces surround expresions: <Class Source='{ concat("t", "ttt") }'> would work. Similarly you can write <boy>{ concat('dirt', 'noise') }</boy> of course. Liam