(* 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 direction = [ `Left | `Right ]
type reduction_kind = [ `Reduce | `Simpl | `Whd ]
(* type 'term pattern = Pattern of 'term *)

  (* everywhere includes goal and hypotheses *)
type 'term pattern = [ `Goal | `Everywhere ]

  (* when an 'ident option is None, the default is to apply the tactic
  to the current goal *)

type loc = CicAst.location

type ('term, 'ident) tactic =
  | Absurd of loc * 'term
  | Apply of loc * 'term
  | Auto of loc * int option
  | Assumption of loc
  | Change of loc * 'term * 'term * 'ident option (* what, with what, where *)
  | Change_pattern of loc * 'term pattern * 'term * 'ident option
      (* what, with what, where *)
  | Contradiction of loc
  | Cut of loc * 'term
  | Decompose of loc * 'ident * 'ident list (* where, which principles *)
  | Discriminate of loc * 'ident
  | Elim of loc * 'term * 'term option (* what to elim, which principle to use *)
  | ElimType of loc * 'term
  | Exact of loc * 'term
  | Exists of loc
  | Fold of loc * reduction_kind * 'term
  | Fourier of loc
  | Goal of loc * int (* change current goal, argument is goal number 1-based *)
  | Injection of loc * 'ident
  | Intros of loc * int option * 'ident list
  | Left of loc
  | LetIn of loc * 'term * 'ident
(*   | Named_intros of loc * 'ident list (* joined with Intros above *) *)
(*   | Reduce of loc * reduction_kind * 'term pattern * 'ident option (* what, where *) *)
  | Reduce of loc * reduction_kind * ('term list * 'term pattern) option
      (* kind, (what, where)
      * if second argument is None, reduction is applied to the current goal,
      * otherwise to each occurrence of loc * terms given in list occuring in term
      * pattern *)
  | Reflexivity of loc
  | Replace of loc * 'term * 'term (* what, with what *)
  | Replace_pattern of loc * 'term pattern * 'term
  | Rewrite of loc * direction * 'term * 'ident option
  | Right of loc
  | Ring of loc
  | Split of loc
  | Symmetry of loc
  | Transitivity of loc * 'term

type thm_flavour =
  [ `Definition
  | `Fact
  | `Lemma
  | `Remark
  | `Theorem
  ]

  (** <name, inductive/coinductive, type, constructor list>
  * true means inductive, false coinductive *)
type 'term inductive_type = string * bool * 'term * (string * 'term) list

type search_kind = [ `Locate | `Hint | `Match | `Elim ]

type print_kind = [ `Env | `Coer ]

type 'term macro = 
  (* Whelp's stuff *)
  | WHint of loc * 'term 
  | WMatch of loc * 'term 
  | WInstance of loc * 'term 
  | WLocate of loc * string
  | WElim of loc * 'term
  (* real macros *)
  | Abort of loc
  | Print of loc * string
  | Check of loc * 'term 
  | Hint of loc
  | Quit of loc
  | Redo of loc * int option
  | Undo of loc * int option
(*   | Print of loc * print_kind *)
  | Search_pat of loc * search_kind * string  (* searches with string pattern *)
  | Search_term of loc * search_kind * 'term  (* searches with term pattern *)

type alias_spec =
  | Ident_alias of string * string        (* identifier, uri *)
  | Symbol_alias of string * int * string (* name, instance no, description *)
  | Number_alias of int * string          (* instance no, description *)

type 'term command =
  | Set of loc * string * string
  | Qed of loc
      (** name.
       * Name is needed when theorem was started without providing a name
       *)
  | Inductive of loc * (string * 'term) list * 'term inductive_type list
      (** parameters, list of loc * mutual inductive types *)
  | Theorem of loc * thm_flavour * string option * 'term * 'term option
      (** flavour, name, type, body
       * - name is absent when an unnamed theorem is being proved, tipically in
       *   interactive usage
       * - body is present when its given along with the command, otherwise it
       *   will be given in proof editing mode using the tactical language
       *)
  | Coercion of loc * 'term
  | Alias of loc * alias_spec

type ('term, 'ident) tactical =
  | Tactic of loc * ('term, 'ident) tactic
  | Fail of loc
  | Do of loc * int * ('term, 'ident) tactical
  | IdTac of loc
  | Repeat of loc * ('term, 'ident) tactical
  | Seq of loc * ('term, 'ident) tactical list (* sequential composition *)
  | Then of loc * ('term, 'ident) tactical * ('term, 'ident) tactical list
  | Tries of loc * ('term, 'ident) tactical list
      (* try a sequence of loc * tacticals until one succeeds, fail otherwise *)
  | Try of loc * ('term, 'ident) tactical (* try a tactical and mask failures *)


type ('term, 'ident) code =
  | Command of loc * 'term command
  | Macro of loc * 'term macro 
      (* Macro are substantially queries, but since we are not the kind of
       * peolpe that like to push "start" to turn off the computer 
       * we added this command *)
  | Tactical of loc * ('term, 'ident) tactical
             
type ('term, 'ident) comment =
  | Note of loc * string
  | Code of loc * ('term, 'ident) code
             
type ('term, 'ident) statement =
  | Executable of loc * ('term, 'ident) code
  | Comment of loc * ('term, 'ident) comment