def expand( path )
path = path.kind_of?(String) ? parse( path ) : path
string = ""
document = false
while path.size > 0
op = path.shift
case op
when :node
string << "node()"
when :attribute, :child, :following, :following_sibling,
:ancestor, :ancestor_or_self, :descendant, :descendant_or_self,
:namespace, :preceding, :preceding_sibling, :self, :parent
string << "/" unless string.size == 0
string << op.to_s.tr("_", "-")
string << "::"
when :any
string << "*"
when :qname
prefix = path.shift
name = path.shift
string << prefix+":" if prefix.size > 0
string << name
when :predicate
string << '['
string << predicate_to_string( path.shift ) { |x| expand(x) }
string << ']'
when :document
document = true
else
string << "/" unless string.size == 0
string << "UNKNOWN("
string << op.inspect
string << ")"
end
end
string = "/"+string if document
return string
end