(* Copyright (C) 2004, 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://helm.cs.unibo.it/
 *)

type state_tag = [ `Command | `Proof ]

class type interpreterState =
  object
      (** eval a toplevel phrase in the current state and return the new state
      *)
    method evalPhrase: string -> state_tag
  end

class commandState
  ~(disambiguator: MatitaTypes.disambiguator)
  ~(proof_handler: MatitaTypes.proof_handler)
  ~(console: MatitaConsole.console)
  ()
=
  object
    method evalPhrase s: state_tag =
      let command = CicTextualParser2.parse_command (Stream.of_string s) in
      match command with
      | CommandAst.Theorem (_, _, Some name, ast, None) ->
          let (_, metasenv, expr) = disambiguator#disambiguateTermAst ast in
          let _  = CicTypeChecker.type_of_aux' metasenv [] expr in
          let proof = MatitaProof.proof ~typ:expr ~metasenv () in
          proof_handler.MatitaTypes.new_proof proof;
          `Proof
      | CommandAst.Quit _ ->
          proof_handler.MatitaTypes.quit ();
          `Command (* dummy answer *)
      | _ ->
          MatitaTypes.not_implemented (* TODO Zack *)
            "MatitaInterpreter.commandState#evalPhrase: commands other than full theorem ones";
          `Proof
  end

  (* TODO Zack FINQUI
  * bisogna rivedere la grammatica di tatticali/comandi
  * molti comandi (o addirittura tutti tranne Theorem) hanno senso anche nello
  * stato proof, e' quindi un casino parsare la phrase. Un'idea potrebbe essere
  * quella di tentare di parsare una tattica e se il parsing fallisce provare a
  * parsare un comando (BLEAARGH). Oppure si puo' aggiungere una possibile entry
  * nella grammatica delle tattiche che punti ad un comando (RI-BLEAARGH).
  * Oppure boh ...
  *)
class proofState
  ~(disambiguator: MatitaTypes.disambiguator)
  ~(proof_handler: MatitaTypes.proof_handler)
  ~(console: MatitaConsole.console)
  ()
=
  object
    method evalPhrase (s: string): state_tag =
      (* TODO Zack *)
      MatitaTypes.not_implemented "MatitaInterpreter.proofState#evalPhrase";
      `Command
  end

class interpreter
  ~(disambiguator: MatitaTypes.disambiguator)
  ~(proof_handler: MatitaTypes.proof_handler)
  ~(console: MatitaConsole.console)
  ()
=
  let commandState =
    lazy (new commandState ~disambiguator ~proof_handler ~console ())
  in
  let proofState =
    lazy (new proofState ~disambiguator ~proof_handler ~console ())
  in
  object
    val mutable state = Lazy.force commandState

    method evalPhrase s =
      match state#evalPhrase s with
      | `Command -> state <- Lazy.force commandState
      | `Proof -> state <- Lazy.force proofState
  end