[XQuery] Inconsistent syntax for variable declarations

I am raising this comment because I have seen several XQuery users make
mistakes as a result of the syntactic inconsistency between global
variable declarations and local variables, and there seems to be no good
reason why they are so different.

For global variables we write:

   declare variable $x [as xs:integer] {3};

while for local variables we write:

   let $x [as xs:integer] := 3

I suggest changing the global variable syntax to:

   declare variable $x [as xs:integer] := 3;

An external variable would be:

   declare variable $x [as xs:integer] external;

Michael Kay