I remember reading somewhere that XPath could potentially process the components of an expression in //, so my question is: Can I define a variable and use it in an other variable definition of the “same” let? For example:

let
    $a := //abc,
    $x := $a/xyz
return
    $x

Or, to be on the safe side, do I need to write:

let $a := //abc return
let $x := $a/xyz return
$x