[Exist-open] declare variable statement not W3C compliant

[Golgoth 14 <gol...@no...>]

On the 20050805 snapshot, the declare variable
statement is not W3C compliant.

W3C statement:
    declare variable $x as xs:integer := 7;

eXist statement:
    declare variable $x as xs:integer {7};

Why this statement is not W3C compliant ?
This is a problem because the queries are not "portable" on other XMLDB 
or XQuery engine !