parserDidStartDocument:
parser:didStartMappingPrefix:toURI: gs http://gnustep.org/example#
parser:didStartElement:namespaceURI:qualifiedName:attributes: node  node {
    "gs:attr" = foo;
}

content
parser:didEndElement:namespaceURI:qualifiedName: node  node
parser:didEndMappingPrefix: gs
parserDidEndDocument: