addOrOpenColumn

  function addOrOpenColumn(tab, colName, dataType, units, comment)&
  result(col)
    type(TableT),   intent(in)           :: tab
    character(*),   intent(in)           :: colName
    integer(int32), intent(in), optional :: dataType
    character(*),   intent(in), optional :: units, comment
    type(ColumnT)                        :: col
  end function addOrOpenColumn

This function opens the column if hasColumn(tab, colName) returns TRUE but adds a new column of this name if not. If a new column is creatd, defaults for the optional arguments `dataType', `units' and `comment' are REAL32, `' and `' respectively.