(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, * CNRS-Ecole Polytechnique-INRIA Futurs-Universite Paris Sud *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)

(*i $Id$ i*)

open Names
open Term

(*s Substitutions *)

type substitution

val empty_subst : substitution

val add_msid : 
  mod_self_id -> module_path -> substitution -> substitution
val add_mbid : 
  mod_bound_id -> module_path -> substitution -> substitution

val map_msid : mod_self_id -> module_path -> substitution
val map_mbid : mod_bound_id -> module_path -> substitution

(* sequential composition: 
   [substitute (join sub1 sub2) t = substitute sub2 (substitute sub1 t)]
*)
val join : substitution -> substitution -> substitution

type 'a substituted
val from_val : 'a -> 'a substituted
val force : (substitution -> 'a -> 'a) -> 'a substituted -> 'a
val subst_substituted : substitution -> 'a substituted -> 'a substituted

(*i debugging *)
val debug_string_of_subst : substitution -> string
val debug_pr_subst : substitution -> Pp.std_ppcmds
(*i*)

(* [subst_mp sub mp] guarantees that whenever the result of the
   substitution is structutally equal [mp], it is equal by pointers 
   as well [==] *) 

val subst_mp : 
  substitution -> module_path -> module_path

(* [occur_*id id sub] returns true iff [id] occurs in [sub] 
   on either side *)

val occur_msid : mod_self_id -> substitution -> bool
val occur_mbid : mod_bound_id -> substitution -> bool

val subst_kn : substitution -> kernel_name -> kernel_name
val subst_con : substitution -> constant -> constant

(* [subst_mps sub c] performs the substitution [sub] on all kernel
   names appearing in [c] *)
val subst_mps : substitution -> constr -> constr