1 (* Copyright (C) 2000, HELM Team.
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4 * Library of Mathematics, developed at the Computer Science
5 * Department, University of Bologna, Italy.
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27 * implementazione del comando UNION
34 let xres_fill_context hr h1 l1 =
38 let hh = List.combine h1 l1
42 if (List.mem_assoc x hh) then
51 * implementazione del comando UNION
53 let union_ex alist1 alist2 =
54 let head1 = List.hd alist1
55 and tail1 = List.tl alist1
56 and head2 = List.hd alist2
57 and tail2 = List.tl alist2 (* e fin qui ... *)
59 match (head1, head2) with
60 ([], _) -> assert false (* gli header non devono mai essere vuoti *)
61 | (_, []) -> assert false (* devono contenere almeno [retVal] *)
62 | (_, _) -> let headr = (head2 @
64 (function t -> not (List.mem t head2))
66 ) in (* header del risultato finale *)
67 List.append (* il risultato finale e' la concatenazione ...*)
68 [headr] (* ... dell'header costruito prima ...*)
70 (fun l m -> List.hd l < List.hd m)
71 (match (tail1, tail2) with (* e di una coda "unione" *)
72 ([], _) -> tail2 (* va bene perche' l'altra lista e' vuota *)
73 | (_, []) -> tail1 (* va bene perche' l'altra lista e' vuota *)
75 let first = (* parte dell'unione che riguarda solo il primo set *)
80 xres_fill_context (List.tl headr) (List.tl head1) (List.tl l)
86 let y = (* elemento candidato ad entrare *)
90 (List.tl headr) (List.tl head2) (List.tl x)
92 par @ if (List.find_all (fun t -> t = y) par) = [] then
97 first (* List.fold_left *)
98 tail2 (* List.fold_left *)
100 List.map (fun l -> [List.hd l] @
102 (List.tl headr) (List.tl head2) (List.tl l)
110 (* preserves order and gets rid of duplicates *)
111 let rec union_ex l1 l2 =
112 let module S = Mathql_semantics in
116 | ({S.uri = uri1} as entry1)::tl1,
117 ({S.uri = uri2} as entry2)::_ when uri1 < uri2 ->
118 entry1::(union_ex tl1 l2)
119 | ({S.uri = uri1} as entry1)::_,
120 ({S.uri = uri2} as entry2)::tl2 when uri2 < uri1 ->
121 entry2::(union_ex l1 tl2)
122 | entry1::tl1,entry2::tl2 -> (* same entry *)
123 if entry1 = entry2 then (* same attributes *)
124 entry1::(union_ex tl1 tl2)
130 let before = Unix.time () in
131 let res = union_ex l1 l2 in
132 let after = Unix.time () in
133 let ll1 = string_of_int (List.length l1) in
134 let ll2 = string_of_int (List.length l2) in
135 let diff = string_of_float (after -. before) in
136 prerr_endline ("UNION(" ^ ll1 ^ "," ^ ll2 ^ "): " ^ diff ^ "s") ;