whitespace between schemes

Right now "xpointer(...)xpointer(...)" is legal, but xpointer(...)
xpointer(...) is not, while the second may be more readable in some
contexts, e.g.

  <href>foo.xml#xpointer(...)
                xpointer(...)</href>

Should optional whitespace be allowed between schemes?  

Not a big deal, but it seems strange that whitespace is allowed within the
parens, but not between schemes.

  <href>foo.xml#xpointer(...
               )xpointer(...)</href>


Is legal, but the top example currently isn't.