sig
type physical_dom_type = PT_CursorSeq | PT_ListSeq
type physical_sax_type = PT_Stream | PT_Discarded
type physical_xml_type =
PT_Dom of Xquery_physical_type_ast.physical_dom_type
| PT_Sax of Xquery_physical_type_ast.physical_sax_type
type physical_variable_type =
Xquery_common_ast.cvname * Xquery_physical_type_ast.physical_xml_type
type physical_tuple_field_type =
Xquery_common_ast.crname * Xquery_physical_type_ast.physical_xml_type
type physical_tuple_type =
Xquery_physical_type_ast.physical_tuple_field_type list
type physical_type =
PT_XML of Xquery_physical_type_ast.physical_xml_type
| PT_Table of Xquery_physical_type_ast.physical_tuple_type
end