(* This file is part of licht. licht is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. licht is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with licht. If not, see . *) module type SYM_TYPE = sig type 'a t type 'a obs val str : DataType.String.t -> DataType.String.t t val num : DataType.Num.t -> DataType.Num.t t val date: DataType.Num.t -> DataType.Num.t t val bool : DataType.Bool.t -> DataType.Bool.t t val observe : 'a t -> 'a obs end