Re: Seek an XPath 2.0 expression that handles an empty

On Thu, Sep 22, 2016 at 04:01:39PM -0000, G. Ken Holman g.ken.holman@xxxxxxxxx scripsit:
> At 2016-09-22 15:55 +0000, Costello, Roger L. costello@xxxxxxxxx wrote:
> > I want an XPath 2.0 expression that outputs "do action" if the B field
> > is empty, regardless of which of the two XML representations is used.
> > This XPath expression seems to work:
> > 
> > if (not(B) or B eq '') then "do action" else "no action"
> 
> This gives you the same result:
> 
> if (not(string(B))) then "do action" else "no action"

You could also use

if (not(boolean(B))) then "do action" else "no action"

which exploits empty strings being false().

Though that's definitely the sort of logic that should get a comment
explaining to your future self what you're going.

-- Graydon