Question

My XQuery knowledge is pretty lacking but I’m trying to play around with XQIB (XQuery in the Browser), but even just setting a variable errors

let $foo := "bar"

…generates the error

MXQuery output the following error during compilation:
Line 1, Column 18: err:XPST0003 Error while parsing FFLWOR Expr: 'return' expected!
let $foo := "bar"    ERROR                        
Unknown.anonymous(Unknown Source)

I’ve looked at the samples on the XQIB site, and it seems the let statements there are always in sub-routines, e.g. alerts or functions. Is this to suggest that in XQuery, code must always live in a function of sorts, rather than be free-standing?

For example, one of their examples is this, which of course works:

b:alert(
    let $x := <a><b>2</b><c>4</c></a>
    return xs:string($x/b * $x/c)
)

But this, my altered version, doesn’t.

let $x := <a><b>2</b><c>4</c></a>
b:alert(
    return xs:string($x/b * $x/c)
)

What’s up with the latter? Thanks in advance for any help.

Answer 1

Your return is at the wrong position:

let $x := <a><b>2</b><c>4</c></a>
return
    b:alert(
        xs:string($x/b * $x/c)
    )

You only need a return if you used some (part of a) flwor-expression. let starts one, so you will need return after it. As you haven’t got one as parameter, you don’t need (and neither are allowed) to put a return here.