In some languages you don't give field names, just types. You bind fields to names only when pattern matching. For example in Haskell:

    type Year = Int
    type Month = Int
    type Day = Int

    -- fields have no names, just types
    data Date = Date Year Month Day

    -- we bind fields to names only when necessary
    next (Date y 12 31) = Date (y + 1) 1 1
    next (Date y m d)
      | d == daysOf m = Date y (m + 1) 1
      | otherwise     = Date y m (d + 1)
      where daysOf = (!!) [0, 31, 28, 31, 30,
                              31, 30, 31, 31,
                              30, 31, 30, 31]

Is something like this what you mean?