--- /dev/null
+(*
+ ||M|| This file is part of HELM, an Hypertextual, Electronic
+ ||A|| Library of Mathematics, developed at the Computer Science
+ ||T|| Department, University of Bologna, Italy.
+ ||I||
+ ||T|| HELM is free software; you can redistribute it and/or
+ ||A|| modify it under the terms of the GNU General Public License
+ \ / version 2 or (at your option) any later version.
+ \ / This software is distributed as is, NO WARRANTY.
+ V_______________________________________________________________ *)
+
+(* $Id$ *)
+
+module DiscriminationTreeIndexing =
+ functor (A:Set.S) ->
+ struct
+
+ type path_string_elem =
+ | Constant of NUri.uri
+ | Bound of int | Variable | Proposition | Datatype | Dead;;
+ type path_string = path_string_elem list;;
+
+
+ (* needed by the retrieve_* functions, to know the arities of the
+ * "functions" *)
+
+ let ppelem = function
+ | Constant uri -> NUri.name_of_uri uri
+ | Bound i -> string_of_int i
+ | Variable -> "?"
+ | Proposition -> "Prop"
+ | Datatype -> "Type"
+ | Dead -> "DEAD"
+ ;;
+ let pppath l = String.concat "::" (List.map ppelem l) ;;
+ let elem_of_cic = function
+ | NCic.Meta _ | NCic.Implicit _ -> Variable
+ | NCic.Rel i -> Bound i
+ | NCic.Sort (NCic.Prop) -> Proposition
+ | NCic.Sort _ -> Datatype
+ | NCic.Const _ | NCic.Var _ | NCic.MutInd _ | NCic.MutConstruct _ as t ->
+ (try Constant (CicUtil.uri_of_term t)
+ with Invalid_argument _ -> assert false)
+ | NCic.Appl _ ->
+ assert false (* should not happen *)
+ | NCic.LetIn _ | NCic.Lambda _ | NCic.Prod _ | NCic.Cast _
+ | NCic.MutCase _ | NCic.Fix _ | NCic.CoFix _ ->
+ HLog.debug "FIXME: the trie receives an invalid term";
+ Dead
+ (* assert false universe.ml removes these *)
+ ;;
+ let path_string_of_term arities =
+ let set_arity arities k n =
+ (assert (k<>Variable || n=0);
+ if k = Dead then arities else (k,n)::(List.remove_assoc k arities))
+ in
+ let rec aux arities = function
+ | NCic.Appl ((hd::tl) as l) ->
+ let arities =
+ set_arity arities (elem_of_cic hd) (List.length tl) in
+ List.fold_left
+ (fun (arities,path) t ->
+ let arities,tpath = aux arities t in
+ arities,path@tpath)
+ (arities,[]) l
+ | t -> arities, [elem_of_cic t]
+ in
+ aux arities
+ ;;
+ let compare_elem e1 e2 =
+ match e1,e2 with
+ | Constant u1,Constant u2 -> NUri.compare u1 u2
+ | e1,e2 -> Pervasives.compare e1 e2
+ ;;
+
+ module OrderedPathStringElement = struct
+ type t = path_string_elem
+ let compare = compare_elem
+ end
+
+ module PSMap = Map.Make(OrderedPathStringElement);;
+
+ type key = PSMap.key
+
+ module DiscriminationTree = Trie.Make(PSMap);;
+
+ type t = A.t DiscriminationTree.t * (path_string_elem*int) list
+ let empty = DiscriminationTree.empty, [] ;;
+
+ let iter (dt, _ ) f =
+ DiscriminationTree.iter (fun _ x -> f x) dt
+ ;;
+
+ let index (tree,arity) term info =
+ let arity,ps = path_string_of_term arity term in
+ let ps_set =
+ try DiscriminationTree.find ps tree
+ with Not_found -> A.empty in
+ let tree = DiscriminationTree.add ps (A.add info ps_set) tree in
+ tree,arity
+ ;;
+
+ let remove_index (tree,arity) term info =
+ let arity,ps = path_string_of_term arity term in
+ try
+ let ps_set = A.remove info (DiscriminationTree.find ps tree) in
+ if A.is_empty ps_set then
+ DiscriminationTree.remove ps tree,arity
+ else
+ DiscriminationTree.add ps ps_set tree,arity
+ with Not_found ->
+ tree,arity
+ ;;
+
+ let in_index (tree,arity) term test =
+ let arity,ps = path_string_of_term arity term in
+ try
+ let ps_set = DiscriminationTree.find ps tree in
+ A.exists test ps_set
+ with Not_found ->
+ false
+ ;;
+
+ let head_of_term = function
+ | NCic.Appl (hd::tl) -> hd
+ | term -> term
+ ;;
+
+ let rec skip_prods = function
+ | NCic.Prod (_,_,t) -> skip_prods t
+ | term -> term
+ ;;
+
+ let rec subterm_at_pos pos term =
+ match pos with
+ | [] -> term
+ | index::pos ->
+ match term with
+ | NCic.Appl l ->
+ (try subterm_at_pos pos (List.nth l index)
+ with Failure _ -> raise Not_found)
+ | _ -> raise Not_found
+ ;;
+
+
+ let rec after_t pos term =
+ let pos' =
+ match pos with
+ | [] -> raise Not_found
+ | pos ->
+ List.fold_right
+ (fun i r -> if r = [] then [i+1] else i::r) pos []
+ in
+ try
+ ignore(subterm_at_pos pos' term ); pos'
+ with Not_found ->
+ let pos, _ =
+ List.fold_right
+ (fun i (r, b) -> if b then (i::r, true) else (r, true))
+ pos ([], false)
+ in
+ after_t pos term
+ ;;
+
+
+ let next_t pos term =
+ let t = subterm_at_pos pos term in
+ try
+ let _ = subterm_at_pos [1] t in
+ pos @ [1]
+ with Not_found ->
+ match pos with
+ | [] -> [1]
+ | pos -> after_t pos term
+ ;;
+
+ let retrieve_generalizations (tree,arity) term =
+ let term = skip_prods term in
+ let rec retrieve tree term pos =
+ match tree with
+ | DiscriminationTree.Node (Some s, _) when pos = [] -> s
+ | DiscriminationTree.Node (_, map) ->
+ let res =
+ let hd_term =
+ elem_of_cic (head_of_term (subterm_at_pos pos term))
+ in
+ if hd_term = Variable then A.empty else
+ try
+ let n = PSMap.find hd_term map in
+ match n with
+ | DiscriminationTree.Node (Some s, _) -> s
+ | DiscriminationTree.Node (None, _) ->
+ let newpos =
+ try next_t pos term
+ with Not_found -> []
+ in
+ retrieve n term newpos
+ with Not_found ->
+ A.empty
+ in
+ try
+ let n = PSMap.find Variable map in
+ let newpos = try after_t pos term with Not_found -> [-1] in
+ if newpos = [-1] then
+ match n with
+ | DiscriminationTree.Node (Some s, _) -> A.union s res
+ | _ -> res
+ else
+ A.union res (retrieve n term newpos)
+ with Not_found ->
+ res
+ in
+ retrieve tree term []
+ ;;
+
+
+ let jump_list arities = function
+ | DiscriminationTree.Node (value, map) ->
+ let rec get n tree =
+ match tree with
+ | DiscriminationTree.Node (v, m) ->
+ if n = 0 then
+ [tree]
+ else
+ PSMap.fold
+ (fun k v res ->
+ let a =
+ try List.assoc k arities
+ with Not_found -> 0
+ in
+ (get (n-1 + a) v) @ res) m []
+ in
+ PSMap.fold
+ (fun k v res ->
+ let arity =
+ try
+ List.assoc k arities
+ with Not_found -> 0 in
+ (get arity v) @ res)
+ map []
+ ;;
+
+
+ let retrieve_unifiables (tree,arities) term =
+ let term = skip_prods term in
+ let rec retrieve tree term pos =
+ match tree with
+ | DiscriminationTree.Node (Some s, _) when pos = [] -> s
+ | DiscriminationTree.Node (_, map) ->
+ let subterm =
+ try Some (subterm_at_pos pos term) with Not_found -> None
+ in
+ match subterm with
+ | None -> A.empty
+ | Some (NCic.Meta _) ->
+ let newpos = try next_t pos term with Not_found -> [] in
+ let jl = jump_list arities tree in
+ List.fold_left
+ (fun r s -> A.union r s)
+ A.empty
+ (List.map (fun t -> retrieve t term newpos) jl)
+ | Some subterm ->
+ let res =
+ let hd_term = elem_of_cic (head_of_term subterm) in
+ if hd_term = Variable then
+ A.empty else
+ try
+ let n = PSMap.find hd_term map in
+ match n with
+ | DiscriminationTree.Node (Some s, _) -> s
+ | DiscriminationTree.Node (None, _) ->
+ retrieve n term (next_t pos term)
+ with Not_found ->
+ A.empty
+ in
+ try
+ let n = PSMap.find Variable map in
+ let newpos =
+ try after_t pos term
+ with Not_found -> [-1]
+ in
+ if newpos = [-1] then
+ match n with
+ | DiscriminationTree.Node (Some s, _) ->
+ A.union s res
+ | _ -> res
+ else
+ A.union res (retrieve n term newpos)
+ with Not_found ->
+ res
+ in
+ retrieve tree term []
+ end
+;;
+
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