* implementazione del comando UNION
*)
+(*
(*
*
*)
head1)
) in (* header del risultato finale *)
List.append (* il risultato finale e' la concatenazione ...*)
- [headr] (* ... dell'header costruito prima ...*)
- (match (tail1, tail2) with (* e di una coda "unione" *)
- ([], _) -> tail2 (* va bene perche' l'altra lista e' vuota *)
- | (_, []) -> tail1 (* va bene perche' l'altra lista e' vuota *)
- | (_, _) ->
- let first = (* parte dell'unione che riguarda solo il primo set *)
- List.map (fun l -> [List.hd l] @
- xres_fill_context
- (List.tl headr) (List.tl head1) (List.tl l)
- ) tail1
- in
- List.fold_left
- (fun par x ->
- let y = (* elemento candidato ad entrare *)
- [List.hd x]
- @
- xres_fill_context
- (List.tl headr) (List.tl head2) (List.tl x)
- in
- par @ if (List.find_all (fun t -> t = y) par) = [] then
- [y]
- else
- []
- )
- first
- tail2
+ [headr] (* ... dell'header costruito prima ...*)
+ (Sort.list
+ (fun l m -> List.hd l < List.hd m)
+ (match (tail1, tail2) with (* e di una coda "unione" *)
+ ([], _) -> tail2 (* va bene perche' l'altra lista e' vuota *)
+ | (_, []) -> tail1 (* va bene perche' l'altra lista e' vuota *)
+ | (_, _) ->
+ let first = (* parte dell'unione che riguarda solo il primo set *)
+ List.map
+ (
+ fun l ->
+ [List.hd l] @
+ xres_fill_context (List.tl headr) (List.tl head1) (List.tl l)
+ )
+ tail1
+ in
+ List.fold_left
+ (fun par x ->
+ let y = (* elemento candidato ad entrare *)
+ [List.hd x]
+ @
+ xres_fill_context
+ (List.tl headr) (List.tl head2) (List.tl x)
+ in
+ par @ if (List.find_all (fun t -> t = y) par) = [] then
+ [y]
+ else
+ []
+ )
+ first (* List.fold_left *)
+ tail2 (* List.fold_left *)
(* first @
List.map (fun l -> [List.hd l] @
xres_fill_context
(List.tl headr) (List.tl head2) (List.tl l)
) tail2
*)
- ) (* match *)
+ ) (* match *)
+ )
+;;
+*)
+(* Merges two attribute group lists preserves order and gets rid of duplicates*)
+let rec merge l1 l2 =
+ match (l1,l2) with
+ [],l
+ | l,[] -> l
+ | g1::tl1,g2::_ when g1 < g2 -> g1::(merge tl1 l2)
+ | g1::_,g2::tl2 when g2 < g1 -> g2::(merge l1 tl2)
+ | g1::tl1,g2::tl2 -> g1::(merge tl1 tl2)
+;;
+
+(* preserves order and gets rid of duplicates *)
+let rec union_ex rs1 rs2 =
+ match (rs1, rs2) with
+ [],l
+ | l,[] -> l
+ | (uri1,l1)::tl1,(uri2,_)::_ when uri1 < uri2 -> (uri1,l1)::(union_ex tl1 rs2)
+ | (uri1,_)::_,(uri2,l2)::tl2 when uri2 < uri1 -> (uri2,l2)::(union_ex rs1 tl2)
+ | (uri1,l1)::tl1,(uri2,l2)::tl2 -> if l1 = l2 then (uri1,l1)::(union_ex tl1 tl2)
+ else (uri1,merge l1 l2)::(union_ex tl1 tl2)
;;
+let union_ex l1 l2 =
+ let before = Unix.time () in
+ let res = union_ex l1 l2 in
+ let after = Unix.time () in
+ let ll1 = string_of_int (List.length l1) in
+ let ll2 = string_of_int (List.length l2) in
+ let diff = string_of_float (after -. before) in
+ print_endline ("UNION(" ^ ll1 ^ "," ^ ll2 ^ "): " ^ diff ^ "s") ;
+ flush stdout ;
+ res
+;;