--- /dev/null
+(***********************************************************************)
+(* *)
+(* 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
+open Misc
+
+(*
+
+(** Implementation of hashconsed Boolean formulae *)
+
+*)
+module type ATOM =
+sig
+ include Hcons.S
+ 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 * bool
+
+module Make (A: ATOM) =
+struct
+
+
+ type 'hcons node = {
+ pos : ('hcons,A.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, b1), Atom(p2, b2) -> p1 == p2 && b1 == b2
+ | _ -> 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, b) -> HASHINT3(PRIME5, Uid.to_int (A.uid p), int_of_bool b)
+ 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,b) -> fprintf ppf "%s%a" (if b then "" else Pretty.lnot) A.print p
+ 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 =
+ let a, _ = cons (Atom(p, true)) (Atom(p, false)) in a
+
+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
projects / tatoo.git / blobdiff