test.rnc

start = Tickmarks

Tickmarks = element tickmarks { 
    (
     attribute from { xsd:float },
     attribute to { xsd:float },
     Tick-float*)
    | (
       attribute from { xsd:date },
       attribute to { xsd:date },
       Tick-date*)
}

Tick-float = element tick { 
    attribute value { xsd:float },
    attribute label { text }
}

Tick-date = element tick { 
    attribute value { xsd:date },
    attribute label { text }
}