Documenting the Tries module, uniformizing the names according to

Map/Set style and renaming the file accordingly as Trie.

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@16504 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 91 insertions, 0 deletions

diff --git a/lib/trie.ml b/lib/trie.ml
new file mode 100644
index 0000000000..d0bcc01554
--- /dev/null
+++ b/lib/trie.ml
@@ -0,0 +1,91 @@
+(************************************************************************)
+(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
+(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2012     *)
+(*   \VV/  **************************************************************)
+(*    //   *      This file is distributed under the terms of the       *)
+(*         *       GNU Lesser General Public License Version 2.1        *)
+(************************************************************************)
+
+module type S =
+sig
+  type label
+  type data
+  type t
+  val empty : t
+  val get : t -> data list
+  val next : t -> label -> t
+  val labels : t -> label list
+  val add : label list -> data -> t -> t
+  val remove : label list -> data -> t -> t
+  val iter : (label list -> data -> unit) -> t -> unit
+end
+
+module Make (Y : Map.OrderedType) (X : Set.OrderedType) =
+struct
+
+module T_dom = Fset.Make(X)
+module T_codom = Fmap.Make(Y)
+
+type data = X.t
+type label = Y.t
+type t = Node of T_dom.t * t T_codom.t
+
+let codom_to_list m = T_codom.fold (fun x y l -> (x,y)::l) m []
+
+let codom_rng m = T_codom.fold (fun _ y acc -> y::acc) m []
+
+let codom_dom m = T_codom.fold (fun x _ acc -> x::acc) m []
+
+let empty = Node (T_dom.empty, T_codom.empty)
+
+let next (Node (_,m)) lbl = T_codom.find lbl m
+
+let get (Node (hereset,_)) = T_dom.elements hereset
+
+let labels (Node (_,m)) = codom_dom m
+
+let in_dom (Node (_,m)) lbl = T_codom.mem lbl m
+
+let is_empty_node (Node(a,b)) = (T_dom.elements a = []) && (codom_to_list b = [])
+
+let assure_arc m lbl =
+  if T_codom.mem lbl m then
+    m
+  else
+    T_codom.add lbl (Node (T_dom.empty,T_codom.empty)) m
+
+let cleanse_arcs (Node (hereset,m)) =
+  let l = codom_rng m in
+  Node(hereset, if List.for_all is_empty_node l then T_codom.empty else m)
+
+let rec at_path f (Node (hereset,m)) = function
+  | [] ->
+      cleanse_arcs (Node(f hereset,m))
+  | h::t ->
+      let m = assure_arc m h in
+      cleanse_arcs (Node(hereset,
+                         T_codom.add h (at_path f (T_codom.find h m) t) m))
+
+let add path v tm =
+  at_path (fun hereset -> T_dom.add v hereset) tm path
+
+let remove path v tm =
+  at_path (fun hereset -> T_dom.remove v hereset) tm path
+
+let iter f tlm =
+  let rec apprec pfx (Node(hereset,m)) =
+    let path = List.rev pfx in
+    T_dom.iter (fun v -> f path v) hereset;
+    T_codom.iter (fun l tm -> apprec (l::pfx) tm) m
+  in
+  apprec [] tlm
+
+let to_list tlm =
+  let rec torec pfx (Node(hereset,m)) =
+    let path = List.rev pfx in
+    List.flatten((List.map (fun v -> (path,v)) (T_dom.elements hereset))::
+		 (List.map (fun (l,tm) -> torec (l::pfx) tm) (codom_to_list m)))
+  in
+  torec [] tlm
+
+end