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

type reduction_kind = [ `Reduce | `Simpl | `Whd ]

type 'term pattern =
  | Pattern of 'term

type location = int * int

type ('term, 'ident) tactic =
  | LocatedTactic of location * ('term, 'ident) tactic

  | Absurd
  | Apply of 'term
  | Assumption
  | Change of 'term * 'term * 'ident option (* what, with what, where *)
  | Change_pattern of 'term pattern * 'term * 'ident option
      (* what, with what, where *)
  | Contradiction
  | Cut of 'term
  | Decompose of 'ident * 'ident list (* which hypothesis, which principles *)
  | Discriminate of 'ident
  | Elim of 'term * 'term option (* what to elim, which principle to use *)
  | ElimType of 'term
  | Exact of 'term
  | Exists
  | Fold of reduction_kind * 'term
  | Fourier
  | Injection of 'ident
  | Intros of int option
  | Left
  | LetIn of 'term * 'ident
  | Named_intros of 'ident list
  | Reduce of reduction_kind * 'term pattern * 'ident option (* what, where *)
  | Reflexivity
  | Replace of 'term * 'term (* what, with what *)
  | Replace_pattern of 'term pattern * 'term
  | RewriteLeft of 'term * 'ident option
  | RewriteRight of 'term * 'ident option
  | Right
  | Ring
  | Split
  | Symmetry
  | Transitivity of 'term

type 'tactic tactical =
  | LocatedTactical of location * 'tactic tactical

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

type binder_kind = [ `Lambda | `Pi | `Exists | `Forall ]
type induction_kind = [ `Inductive | `CoInductive ]
type sort_kind = [ `Prop | `Set | `Type | `CProp ]

type case_pattern = string list

type term =
  | LocatedTerm of location * term

  | Appl of term list
  | Appl_symbol of string * int * term list (* literal, args, instance *)
  | Binder of binder_kind * Cic.name * term option * term
      (* kind, name, type, body *)
  | Case of term * string * term option * (case_pattern * term) list
    (* what to match, inductive type, out type, <pattern,action> list *)
  | LetIn of string * term * term  (* name, body, where *)
  | LetRec of induction_kind * (string * term * term option * int) list * term
      (* (name, body, type, decreasing argument) list, where *)
  | Ident of string * subst list  (* literal, substitutions *)
  | Meta of int * meta_subst list
  | Num of string * int (* literal, instance *)
  | Sort of sort_kind

and meta_subst = term option
and subst = string * term

(*
type cexpr =
  | Symbol of string option * string * (subst option) * string option         
                                     (* h:xref, name, subst, definitionURL *)
  | LocalVar of string option * string        (* h:xref, name *)
  | Meta of string option * string * meta_subst (* h:xref, name, meta_subst *)
  | Num of string option * string             (* h:xref, value *)
  | Appl of string option * cexpr list        (* h:xref, args *)
  | Binder of string option *string * decl * cexpr   
                                       (* h:xref, name, decl, body *)
  | Letin of string option * def * cexpr          (* h:xref, def, body *)
  | Letrec of string option * def list * cexpr    (* h:xref, def list, body *)
  | Case of string option * cexpr * ((string * cexpr) list)
	                       (* h:xref, case_expr, named-pattern list *)
and 
  decl = string * cexpr               (* name, type *)
and
  def = string * cexpr               (* name, body *)
and
  subst = (UriManager.uri * cexpr) list
and
  meta_subst = cexpr option list
*)