(**************************************************************************)
(*                                                                        *)
(*                                  Cubicle                               *)
(*             Combining model checking algorithms and SMT solvers        *)
(*                                                                        *)
(*                  Guillaume Bury                                        *)
(*                  INRIA                                                 *)
(*                  Sylvain Conchon and Alain Mebsout                     *)
(*                  Universite Paris-Sud 11                               *)
(*                                                                        *)
(*  Copyright 2011. This file is distributed under the terms of the       *)
(*  Apache Software License version 2.0                                   *)
(*                                                                        *)
(**************************************************************************)

module type S = sig
  (** Signature of formulas that parametrises the SMT Solver Module. *)

  module Term : sig
    (** The type of terms *)
    type t
    val hash : t -> int
    val equal : t -> t -> bool
    val compare : t -> t -> int
    val print : Format.formatter -> t -> unit
  end

  module Formula : sig
    (** The type of atomic formulas over terms. *)
    type t
    val hash : t -> int
    val equal : t -> t -> bool
    val compare : t -> t -> int
    val print : Format.formatter -> t -> unit
  end

  val dummy : Formula.t
  (** Formula constants. A valid formula should never be physically equal to [dummy] *)

  val fresh : unit -> Formula.t
  (** Returns a fresh litteral, distinct from any other literal (used in cnf conversion) *)

  val neg : Formula.t -> Formula.t
  (** Formula negation *)

  val norm : Formula.t -> Formula.t * bool
  (** Returns a 'normalized' form of the formula, possibly negated (in which case return true).
      [norm] must be so that [a] and [neg a] normalises to the same formula. *)

end