(* Copyright (C) 2000, HELM Team.
 * 
 * This file is part of HELM, an Hypertextual, Electronic
 * Library of Mathematics, developed at the Computer Science
 * Department, University of Bologna, Italy.
 * 
 * HELM 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 2
 * of the License, or (at your option) any later version.
 * 
 * HELM 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 HELM; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA  02111-1307, USA.
 * 
 * For details, see the HELM World-Wide-Web page,
 * http://cs.unibo.it/helm/.
 *)

(*  AUTOR: Ferruccio Guidi <fguidi@cs.unibo.it>
 *)

type flag = Galax | Postgres | Queries | Result | Source | Times | Warn

val string_of_flags : flag list -> string
val flags_of_string : string -> flag list

type handle

val init      : ?flags:(flag list) -> ?log:(string -> unit) -> unit -> handle
val close     : handle -> unit
val connected : handle -> bool
val exec      : handle -> 
                MQITypes.table -> MQITypes.columns ->
                string MQITypes.con_true -> string MQITypes.con_false -> 
	        MQITypes.result * MQITypes.query

val init_if_connected : ?flags:(flag list) -> ?log:(string -> unit) -> unit -> handle

(* The following functions allow to read the handle internal fields. 
 * For exclusive use of the interpreter.  
 *)

val log     : handle -> string -> unit
val set     : handle -> flag -> bool   
val flags   : handle -> flag list  
val tables  : handle -> MathQL.path -> MQIMap.pg_tables
val field   : handle -> MathQL.path -> string -> string
val resolve : handle -> string -> string