Procedural : some improvements

[helm.git] / helm / software / components / acic_procedural / proceduralClassify.ml

diff --git a/helm/software/components/acic_procedural/proceduralClassify.ml b/helm/software/components/acic_procedural/proceduralClassify.ml
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+(* Copyright (C) 2003-2005, HELM Team.
+ * 
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ * 
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 
+ * HELM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA  02111-1307, USA.
+ * 
+ * For details, see the HELM World-Wide-Web page,
+ * http://cs.unibo.it/helm/.
+ *)
+
+module C = Cic
+module R = CicReduction
+module D = Deannotate
+module Int = struct
+   type t = int
+   let compare = compare 
+end
+module S = Set.Make (Int) 
+
+type conclusion = (int * int) option
+
+(* debugging ****************************************************************)
+
+let string_of_entry inverse =
+   if S.mem 0 inverse then "C" else
+   if S.is_empty inverse then "I" else "P"
+
+let to_string (classes, rc) =
+   let linearize = String.concat " " (List.map string_of_entry classes) in
+   match rc with
+      | None        -> linearize
+      | Some (i, j) -> Printf.sprintf "%s %u %u" linearize i j
+
+let out_table b =
+   let map i (_, inverse) =
+      let map i tl = Printf.sprintf "%2u" i :: tl in 
+      let iset = String.concat " " (S.fold map inverse []) in
+      Printf.eprintf "%2u|%s\n" i iset
+   in
+   Array.iteri map b;
+   prerr_newline ()
+   
+(****************************************************************************)
+
+let id x = x
+
+let rec list_fold_left g map = function
+  | []       -> g
+  | hd :: tl -> map (list_fold_left g map tl) hd
+
+let get_rels h t = 
+   let rec aux d g = function
+      | C.Sort _
+      | C.Implicit _       -> g
+      | C.Rel i            -> 
+         if i < d then g else fun a -> g (S.add (i - d + h + 1) a)
+      | C.Appl ss          -> list_fold_left g (aux d) ss
+      | C.Const (_, ss)
+      | C.MutInd (_, _, ss)
+      | C.MutConstruct (_, _, _, ss)
+      | C.Var (_, ss)      -> 
+         let map g (_, t) = aux d g t in 
+        list_fold_left g map ss
+      | C.Meta (_, ss)     ->
+         let map g = function 
+           | None   -> g
+           | Some t -> aux d g t
+        in
+        list_fold_left g map ss
+      | C.Cast (t1, t2)    -> aux d (aux d g t2) t1
+      | C.LetIn (_, t1, t2)
+      | C.Lambda (_, t1, t2)
+      | C.Prod (_, t1, t2) -> aux d (aux (succ d) g t2) t1
+      | C.MutCase (_, _, t1, t2, ss) ->
+        aux d (aux d (list_fold_left g (aux d) ss) t2) t1
+      | C.Fix (_, ss) ->
+         let k = List.length ss in
+        let map g (_, _, t1, t2) = aux d (aux (d + k) g t2) t1 in
+        list_fold_left g map ss
+      | C.CoFix (_, ss) ->
+         let k = List.length ss in
+        let map g (_, t1, t2) = aux d (aux (d + k) g t2) t1 in
+        list_fold_left g map ss
+   in
+   let g a = a in
+   aux 1 g t S.empty
+
+let split c t =
+   let add s v c = Some (s, C.Decl v) :: c in
+   let rec aux whd a n c = function
+      | C.Prod (s, v, t)  -> aux false (v :: a) (succ n) (add s v c) t
+      | v when whd        -> v :: a, n
+      | v                 -> aux true a n c (R.whd ~delta:true c v)
+    in
+    aux false [] 0 c t
+
+let classify_conclusion = function
+   | C.Rel i                -> Some (i, 0)
+   | C.Appl (C.Rel i :: tl) -> Some (i, List.length tl)
+   | _                      -> None
+
+let classify c t =
+try   
+   let vs, h = split c t in
+   let rc = classify_conclusion (List.hd vs) in
+   let map (b, h) v = (get_rels h v, S.empty) :: b, succ h in
+   let l, h = List.fold_left map ([], 0) vs in
+   let b = Array.of_list (List.rev l) in
+   let mk_closure b h =
+      let map j = if j < h then S.union (fst b.(j)) else id in 
+      for i = pred h downto 0 do
+         let direct, unused = b.(i) in
+        b.(i) <- S.fold map direct direct, unused 
+      done; b
+   in
+   let b = mk_closure b h in
+   let rec mk_inverse i direct =
+      if S.is_empty direct then () else
+      let j = S.choose direct in
+      if j < h then
+         let unused, inverse = b.(j) in 
+         b.(j) <- unused, S.add i inverse
+       else ();
+       mk_inverse i (S.remove j direct)
+   in
+   let map i (direct, _) = mk_inverse i direct in
+   Array.iteri map b;
+(*   out_table b; *)
+   List.rev_map snd (List.tl (Array.to_list b)), rc
+with Invalid_argument _ -> failwith "Classify.classify"
+
+let overlaps s1 s2 =
+   let predicate x = S.mem x s1 in
+   S.exists predicate s2