Xquery variable not set - xquery

Question

In my Xquery 3.1 module I have imported my " global variables" through a module import, one of which ($globalvar:MSGS) contains an XML document that I generally have no problems accessing through reference to the variable. For example this
$globalvar:MSGS//vocab[#xml:id="warning"]
will return
<vocab xml:id="warning">
<span lang="en">Warning! Your changes (OBJECTID) could not be saved!</span>
<span lang="fr">Attention, vos modifications (OBJECTID) n’ont pas pu être sauvegardées !</span>
</vocab>
But the following is returning an error err:XPDY0002 variable '$msg' is not set pointing to line 7-8:
1. let $collid := $mydoc//collection-id/text()
2. let $errtitle :=
3. <msg-error-title>
4. {
5. let $msg := $globalvar:MSGS/id("warning")/span
6. return
7. <en>{replace($msg[#lang="en"]/text(),"OBJECTID",$collid)}</en>,
8. <fr>{replace($msg[#lang="fr"]/text(),"OBJECTID",$collid)}</fr>
9. }
10. </msg-error-title>
11. return $errtitle
But if I remove the inner let ... return and make direct reference to $globalvar:MSGS like below, there are no errors:
let $collid := $mydoc//collection-id/text()
let $errtitle :=
<msg-error-title>
{
<en>{replace($globalvar:MSGS/id("warning")/span[#lang="en"]/text(),"OBJECTID",$collid)}</en>,
<fr>{replace($globalvar:MSGS/id("warning")/span[#lang="fr"]/text(),"OBJECTID",$collid)}</fr>
}
</msg-error-title>
return $errtitle
I don't understand why $msg isn't set in the first example? Is there an alternative?
added test
let $collid := "FOOID"
let $xml :=
<vocab xml:id="warning">
<span lang="en">Warning! Your changes (OBJECTID) could not be saved!</span>
<span lang="fr">Attention, vos modifications (OBJECTID) n’ont pas pu être sauvegardées !</span>
</vocab>
let $errtitle :=
<msg-error-title>
{let $msg := $xml/id("warning")/span
return
<en>{replace($msg[#lang="en"]/text(),"OBJECTID",$collid)}</en>,
<fr>{replace($msg[#lang="fr"]/text(),"OBJECTID",$collid)}</fr>
}
</msg-error-title>
return $errtitle

Answer 1

Your test case fails in Saxon with
Static error
XPST0008 Unresolved reference to variable $msg
The problem is that "," doesn't bind as closely as you think, so you need extra parens around the return expression:
return (
<en>{replace($msg[#lang="en"]/text(),"OBJECTID",$collid)}</en>,
<fr>{replace($msg[#lang="fr"]/text(),"OBJECTID",$collid)}</fr>
)