Question

I have a function which contains a constructor:

declare function local:Construct ($id) {   <tag id='{$id}'/> } 

I use the function in return of ‘FLWOR’:

for $val in ... ... return local:Construct(data($val/id)) 

This works.

Now I want to concatenate two Constructs like this

for $val in ... ... return local:Construct(data($val/id1)) + local:Construct(data($val/id2)) 

The plus sign is of course wrong. What should I use instead?

Answer 1

I assume you want to return two nodes for each $val, in which case you want to use the , operator, like so:

for $val in ... ... return (local:Construct(data($val/id1)), local:Construct(data($val/id2))) 

The extra brackets are required, or you will be trying to concatenate local:Construct(data($val/id2)) onto the result of the FLWOR, which would result in an ‘undefined variable’ error.