def to_string(format_uri = nil, base_uri = nil)
if self.is_graph?()
tmpmodel=Model.new()
tmpmodel.add_statements(self.as_stream())
serializer=Serializer.new()
return serializer.model_to_string(base_uri, tmpmodel)
end
if not self.is_boolean?() and not self.is_bindings?()
raise RedlandError.new("Unknown query result format cannot be written as a string")
end
if format_uri
format_uri = format_uri.uri
end
if base_uri
base_uri = base_uri.uri
end
return Redland.librdf_query_results_to_string(@results, format_uri, base_uri)
end