ID.datatype = xsd:ID
LanguageCode.datatype = xsd:language

id.attrib = attribute id { ID.datatype }?
xmlbase.attrib = attribute xml:base { text }?
Core.attrib = id.attrib, xmlbase.attrib
lang.attrib = attribute xml:lang { LanguageCode.datatype }?
I18n.attrib = lang.attrib
Common.attrib = Core.attrib, I18n.attrib

start = file | line | segment | whitespace

file = element file { file.attlist, file.content }
file.attlist = Common.attrib, attribute path { text }, attribute type { text }
file.content = line*

line = element line { line.attlist, line.content }
line.attlist = Common.attrib
line.content = (segment | whitespace)*

segment = element segment { segment.attlist, text }
segment.attlist = Common.attrib, attribute type { text }

whitespace = element whitespace { whitespace.attlist, empty }
whitespace.attlist = Common.attrib