+let prop_pool = ref None;;
+
+*****************************************************************************)
+
+let init () = Dbconn.init ()
+(*
+ let c = pgc () in
+ let res =
+ c#exec "select name,id from property where ns_id in (select id from namespace where url='http://www.cs.unibo.it/helm/schemas/mattone.rdf#')"
+ in
+ prop_pool := Some
+ (
+ List.map
+ (function
+ a::b::_ -> (a, b)
+ | _ -> print_endline "no"; assert false
+ )
+ res#get_list
+ )
+*)
+
+let close () = Dbconn.close ()
+
+let check () = Dbconn.pgc ()
+
+exception BooleExpTrue
+
+(* valuta una MathQL.set_exp e ritorna un MathQL.resource_set *)
+
+let rec exec_set_exp c = function
+ |MathQL.SVar svar -> List.assoc svar c.svars
+ |MathQL.RVar rvar -> [List.assoc rvar c.rvars]
+ | MathQL.Ref vexp -> List.map (fun s -> (s,[])) (exec_val_exp c vexp)
+ | MathQL.Intersect (sexp1, sexp2) -> intersect_ex (exec_set_exp c sexp1) (exec_set_exp c sexp2)
+ | MathQL.Union (sexp1, sexp2) -> union_ex (exec_set_exp c sexp1) (exec_set_exp c sexp2)
+ | MathQL.LetSVar (svar, sexp1, sexp2) -> let _ = (svar, (exec_set_exp c sexp1)):: (List.remove_assoc svar c.svars)
+ in (exec_set_exp c sexp2)
+ | MathQL.LetVVar (vvar, vexp, sexp) -> let _ = (vvar, (exec_val_exp c vexp)):: (List.remove_assoc vvar c.vvars)
+ in (exec_set_exp c sexp)
+ | MathQL.Relation (rop, path, sexp, attl) -> relation_ex rop path (exec_set_exp c sexp) attl
+ | MathQL.Select (rvar, sexp, bexp) -> let rset = (exec_set_exp c sexp) in
+ let rec select_ex rset =
+ match rset with
+ [] -> []
+ | r::tl -> let c1 = upd_rvars c ((rvar,r)::c.rvars) in
+ if (exec_boole_exp c1 bexp) then r::(select_ex tl)
+ else select_ex tl
+ in select_ex rset
+
+
+
+ | MathQL.Diff (sexp1, sexp2) -> diff_ex (exec_set_exp c sexp1) (exec_set_exp c sexp2)
+ | _ -> assert false
+
+(* valuta una MathQL.boole_exp e ritorna un boole *)
+
+and exec_boole_exp c = function
+ | MathQL.False -> false
+ | MathQL.True -> true
+ | MathQL.Not x -> not (exec_boole_exp c x)
+ | MathQL.And (x, y) -> (exec_boole_exp c x) && (exec_boole_exp c y)
+ | MathQL.Or (x, y) -> (exec_boole_exp c x) || (exec_boole_exp c y)
+ | MathQL.Sub (vexp1, vexp2) -> sub_ex (exec_val_exp c vexp1) (exec_val_exp c vexp2)
+ | MathQL.Meet (vexp1, vexp2) -> meet_ex (exec_val_exp c vexp1) (exec_val_exp c vexp2)
+ | MathQL.Eq (vexp1, vexp2) -> (exec_val_exp c vexp1) = (exec_val_exp c vexp2)
+ | MathQL.Ex l bexp ->
+ if l = [] then (exec_boole_exp c bexp)
+ else
+ let latt = List.map (fun uri ->
+ let (r,attl) = List.assoc uri c.rvars
+ in (uri,attl)) l (*latt = l + attributi*)
+ in
+ try
+ let rec prod c = function
+ [] -> if (exec_boole_exp c bexp) then raise BooleExpTrue
+ | (uri,attl)::tail1 -> let rec sub_prod attl =
+ match attl with
+(*per ogni el. di attl *) [] -> ()
+(*devo andare in ric. su tail1*) | att::tail2 -> let c1 = upd_groups c ((uri,att)::c.groups) in
+ prod c1 tail1; sub_prod tail2
+ in
+ sub_prod attl
+ in
+ prod c latt; false
+ with BooleExpTrue -> true
+ | _ -> assert false
+
+(* valuta una MathQL.val_exp e ritorna un MathQL.value *)
+
+and exec_val_exp c = function
+ | MathQL.Const x -> let ol = List.sort compare x in
+ let rec edup = function
+
+ [] -> []
+ | s::tl -> if tl <> [] then
+ if s = (List.hd tl) then edup tl
+ else s::(edup tl)
+ else s::[]
+ in
+ edup ol
+ | MathQL.Record (rvar, vvar) -> List.assoc vvar (List.assoc rvar c.groups)
+
+ | MathQL.VVar s -> List.assoc s c.vvars
+ | MathQL.RefOf sexp -> List.map (fun (s,_) -> s) (exec_set_exp c sexp)
+
+ | _ -> assert false
+
+
+(* valuta una MathQL.set_exp nel contesto vuoto e ritorna un MathQL.resource_set *)
+
+and execute x =
+ exec_set_exp {svars = []; rvars = []; groups = []; vvars = []} x
+
+
+
+