-(***********************************************************************)
-(* *)
-(* TAToo *)
-(* *)
-(* Kim Nguyen, LRI UMR8623 *)
-(* Université Paris-Sud & CNRS *)
-(* *)
-(* Copyright 2010-2013 Université Paris-Sud and Centre National de la *)
-(* Recherche Scientifique. All rights reserved. This file is *)
-(* distributed under the terms of the GNU Lesser General Public *)
-(* License, with the special exception on linking described in file *)
-(* ../LICENSE. *)
-(* *)
-(***********************************************************************)
-
-INCLUDE "utils.ml"
-
-open Format
-
-(*
-
-(** Implementation of hashconsed Boolean formulae *)
-
-*)
-module type ATOM =
-sig
- type t
- val neg : t -> t
- include Hcons.Abstract with type t := t
- include Common_sig.Printable with type t := t
-end
-
-type ('formula,'atom) expr =
- | False
- | True
- | Or of 'formula * 'formula
- | And of 'formula * 'formula
- | Atom of 'atom
-
-module Make (P: ATOM) =
-struct
-
-
- type 'hcons node = {
- pos : ('hcons,P.t) expr;
- mutable neg : 'hcons;
- }
-
- external hash_const_variant : [> ] -> int = "%identity"
- external vb : bool -> int = "%identity"
-
- module rec Node : Hcons.S
- with type data = Data.t = Hcons.Make (Data)
- and Data : Common_sig.HashedType with type t = Node.t node =
- struct
- type t = Node.t node
- let equal x y =
- match x.pos, y.pos with
- | a,b when a == b -> true
- | Or(xf1, xf2), Or(yf1, yf2)
- | And(xf1, xf2), And(yf1,yf2) -> xf1 == yf1 && xf2 == yf2
- | Atom(p1), Atom(p2) -> p1 == p2
- | _ -> false
-
- let hash f =
- match f.pos with
- | False -> 0
- | True -> 1
- | Or (f1, f2) ->
- HASHINT3 (PRIME1, Uid.to_int f1.Node.id, Uid.to_int f2.Node.id)
- | And (f1, f2) ->
- HASHINT3(PRIME3, Uid.to_int f1.Node.id, Uid.to_int f2.Node.id)
- | Atom(p) -> HASHINT2(PRIME5, Uid.to_int (P.uid p))
- end
-
- type t = Node.t
- let hash x = x.Node.hash
- let uid x = x.Node.id
- let equal = Node.equal
- let expr f = f.Node.node.pos
-
- let compare f1 f2 = compare f1.Node.id f2.Node.id
- let prio f =
- match expr f with
- | True | False -> 10
- | Atom _ -> 8
- | And _ -> 6
- | Or _ -> 1
-
- let rec print ?(parent=false) ppf f =
- if parent then fprintf ppf "(";
- let _ = match expr f with
- | True -> fprintf ppf "%s" Pretty.top
- | False -> fprintf ppf "%s" Pretty.bottom
- | And(f1,f2) ->
- print ~parent:(prio f > prio f1) ppf f1;
- fprintf ppf " %s " Pretty.wedge;
- print ~parent:(prio f > prio f2) ppf f2;
- | Or(f1,f2) ->
- (print ppf f1);
- fprintf ppf " %s " Pretty.vee;
- (print ppf f2);
- | Atom(p) -> fprintf ppf "%a" P.print p
-(* let _ = flush_str_formatter() in
- let fmt = str_formatter in
- let a_str, d_str =
- match dir with
- | `Left -> Pretty.down_arrow, Pretty.subscript 1
- | `Right -> Pretty.down_arrow, Pretty.subscript 2
- | `Epsilon -> Pretty.epsilon, ""
- | `Up1 -> Pretty.up_arrow, Pretty.subscript 1
- | `Up2 -> Pretty.up_arrow, Pretty.subscript 2
- in
- fprintf fmt "%s%s" a_str d_str;
- State.print fmt s;
- let str = flush_str_formatter() in
- if b then fprintf ppf "%s" str
- else Pretty.pp_overline ppf str *)
- in
- if parent then fprintf ppf ")"
-
-let print ppf f = print ~parent:false ppf f
-
-let is_true f = (expr f) == True
-let is_false f = (expr f) == False
-
-
-let cons pos neg =
- let nnode = Node.make { pos = neg; neg = Obj.magic 0 } in
- let pnode = Node.make { pos = pos; neg = nnode } in
- (Node.node nnode).neg <- pnode; (* works because the neg field isn't taken into
- account for hashing ! *)
- pnode,nnode
-
-
-let true_,false_ = cons True False
-
-let atom_ p = fst (cons (Atom(p)) (Atom(P.neg p)))
-
-let not_ f = f.Node.node.neg
-
-let order f1 f2 = if uid f1 < uid f2 then f2,f1 else f1,f2
-
-let or_ f1 f2 =
- (* Tautologies: x|x, x|not(x) *)
-
- if equal f1 f2 then f1
- else if equal f1 (not_ f2) then true_
-
- (* simplification *)
- else if is_true f1 || is_true f2 then true_
- else if is_false f1 && is_false f2 then false_
- else if is_false f1 then f2
- else if is_false f2 then f1
-
- (* commutativity of | *)
- else
- let f1, f2 = order f1 f2 in
- fst (cons (Or(f1,f2)) (And(not_ f1, not_ f2)))
-
-
-let and_ f1 f2 =
- not_ (or_ (not_ f1) (not_ f2))
-
-
-let of_bool = function true -> true_ | false -> false_
-
-let fold f phi acc =
- let rec loop phi acc =
- match expr phi with
- | And (phi1, phi2) | Or(phi1, phi2) ->
- loop phi2 (loop phi1 (f phi acc))
- | _ -> f phi acc
- in
- loop phi acc
-
-end