Hi,

> > You seem to be testing if the string value of an
> > attribute is an empty string. Either like already
> > have, or if you want to test if the attribute
> > exists, then simply
> > 
> >   <xsl:when test="@Predecessors">
> 
> Yes, what I am wanting to do is to have an attribute
> in the output document called parent_id.  This
> attribute should have the value of the @Predecessors
> attribute in the source document.  If the
> @Predecessors attribute has the value of an empty
> string, then I want parent_id="1".  Similarly, if
> there is no @Predecessors attribute in the source
> document, I want the parent_id attribute to be
> parent_id="1".

Then test

  <xsl:if test="@Predecessors = ''">

or e.g.

  <xsl:if test="string-length(normalize-space(@Predecessors)) = 0">

I suggest reading the XPath spec at <http://www.w3.org/TR/xpath.html#booleans>.

Cheers,

Jarno