unexpected results in typecasting functionresult

Christian, I encountered some unexpected behavior with the typecasting of functionresult. it is about the "?" in line 4 of both snippets. [expectedResult.xq], the snippet with the " ?" gives the expected result. [unexpectedResult.xq], the snipped without the "?" , gives an unexpected result. Is this a correct observation or am I missing something? mvgr. Rob Stapper

Hi Rob, The spec allows processors to optimize code by taking advantage the supplied type information. For example, the following code…

  let $a as element() := <a/>[. = 'x']
  return empty($a)

…can (and will) be simplified to a static false() – both by BaseX and Saxon, and possibly other processors – because $a is typed to be a single element. Hope this helps, Christian