Is whitespace significant in the XML representation of XACML?

I saw the 
urn:oasis:names:tc:xacml:1.0:function:string-normalize-space function, which would be superfluous if whitespace were *not* significant, so I assume that it is, but I don’t
 see this explicitly stated in the spec. Also, it doesn’t seem to provide a good user experience for those of us unlucky enough to write policies by hand. Thoughts?