[eXist-TEIXML] A branching problem

[Peter W. <pet...@ke...>]

Hi

I'm trying to find a method of getting a program to branch depending on 
the parameter provided.  After determining the selection, the following 
processes are identical.  The following code will only provide data for  
$name-predicate.  If I change the order, it works for a $place-predicate 
only. I presume from this that this particular use of a conditional 
clause is invalid.  What alternatives do I have for achieving the 
desired result? (Apart from separate XQueries which is where I am at the 
moment. I've also tried putting alternatives into the predicate which 
according to Presley p 46 does seem to be legitimate - see below, but 
that does not work either).

Best wishes

Peter

let $name-predicate := 
local:get-name-predicate(request:get-parameter('people',''))
let $place-predicate := 
local:get-name-predicate(request:get-parameter('place',''))
let $selected-documents :=
(if($name-predicate) then 
(collection('/db/punch/data')//tei:persName[@corresp=$name-predicate])
else if($place-predicate) then 
(collection('/db/punch/data')//tei:placeName[@corresp=$place-predicate])
   else ())
return $selected-documents

Alternative predicate:
let $selected-documents := 
collection('/db/punch/data')//(if($name-predicate) then 
tei:persName[@corresp=$name-predicate]
else tei:placeName[@corresp=$place-predicate] )
return $selected-documents

  * Version: 2.0-tech-preview
  * SVN Revision: 15855
  * Build: 20120228