sidekick/solver/theory_intf.ml
2014-12-18 16:04:17 +01:00

61 lines
2.6 KiB
OCaml

(**************************************************************************)
(* *)
(* Cubicle *)
(* Combining model checking algorithms and SMT solvers *)
(* *)
(* Sylvain Conchon, Evelyne Contejean *)
(* Francois Bobot, Mohamed Iguernelala, Alain Mebsout *)
(* CNRS, 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 for theories to be given to the Solver. *)
type formula
(** The type of formulas. Should be compatble with Formula_intf.S *)
type proof
(** A custom type for the proofs of lemmas produced by the theory. *)
type slice = {
start : int;
length : int;
get : int -> formula;
push : formula list -> proof -> unit;
}
(** The type for a slice of litterals to assume/propagate in the theory.
[get] operations should only be used for integers [ start <= i < start + length].
[push clause proof] allows to add a tautological clause to the sat solver. *)
type level
(** The type for levels to allow backtracking. *)
(** Type returned by the theory, either the current set of assumptions is satisfiable,
or it is not, in which case a tautological clause (hopefully minimal) is returned.
Formulas in the unsat clause must come from the current set of assumptions, i.e
must have been encountered in a slice. *)
type res =
| Sat of level
| Unsat of formula list * proof
val dummy : level
(** A dummy level. *)
val current_level : unit -> level
(** Return the current level of the theory (either the empty/beginning state, or the
last level returned by the [assume] function). *)
val assume : slice -> res
(** Assume the formulas in the slice, possibly pushing new formulas to be propagated,
and returns the result of the new assumptions. *)
val backtrack : level -> unit
(** Backtrack to the given level. After a call to [backtrack l], the theory should be in the
same state as when it returned the value [l], *)
end