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)
109 (* Merges two attribute group lists preserves order and gets rid of duplicates*)
110 let rec merge l1 l2 =
114 | g1::tl1,g2::_ when g1 < g2 -> g1::(merge tl1 l2)
115 | g1::_,g2::tl2 when g2 < g1 -> g2::(merge l1 tl2)
116 | g1::tl1,g2::tl2 -> g1::(merge tl1 tl2)
119 (* preserves order and gets rid of duplicates *)
120 let rec union_ex rs1 rs2 =
121 match (rs1, rs2) with
124 | (uri1,l1)::tl1,(uri2,_)::_ when uri1 < uri2 -> (uri1,l1)::(union_ex tl1 rs2)
125 | (uri1,_)::_,(uri2,l2)::tl2 when uri2 < uri1 -> (uri2,l2)::(union_ex rs1 tl2)
126 | (uri1,l1)::tl1,(uri2,l2)::tl2 -> if l1 = l2 then (uri1,l1)::(union_ex tl1 tl2)
127 else (uri1,merge l1 l2)::(union_ex tl1 tl2)
131 let before = Unix.time () in
132 let res = union_ex l1 l2 in
133 let after = Unix.time () in
134 let ll1 = string_of_int (List.length l1) in
135 let ll2 = string_of_int (List.length l2) in
136 let diff = string_of_float (after -. before) in
137 print_endline ("UNION(" ^ ll1 ^ "," ^ ll2 ^ "): " ^ diff ^ "s") ;