X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fextlib%2FhExtlib.ml;h=07886f2690e8eaba64137d434f330793c2423e04;hb=b73c1560045798ff1e77491050409a783d915345;hp=c0364315a62c018923f2c9e76873a35087c15fd2;hpb=abd2098b6c4a40b36bb4b950c607eb4b4a7852bc;p=helm.git

diff --git a/helm/software/components/extlib/hExtlib.ml b/helm/software/components/extlib/hExtlib.ml
index c0364315a..07886f269 100644
--- a/helm/software/components/extlib/hExtlib.ml
+++ b/helm/software/components/extlib/hExtlib.ml
@@ -153,6 +153,28 @@ let rec filter_map f =
       | None -> filter_map f tl
       | Some v -> v :: filter_map f tl)
 
+let list_rev_map_filter f l =
+   let rec aux a = function
+      | []       -> a
+      | hd :: tl -> 
+         begin match f hd with
+	    | None   -> aux a tl
+	    | Some b -> aux (b :: a) tl 
+         end
+   in 
+   aux [] l
+
+let list_rev_map_filter_fold f v l =
+   let rec aux v a = function
+      | []       -> v, a
+      | hd :: tl -> 
+         begin match f v hd with
+	    | v, None   -> aux v a tl
+	    | v, Some b -> aux v (b :: a) tl 
+         end
+   in 
+   aux v [] l
+
 let list_concat ?(sep = []) =
   let rec aux acc =
     function
@@ -192,6 +214,16 @@ let is_dir fname =
     (Unix.stat fname).Unix.st_kind = Unix.S_DIR
   with Unix.Unix_error _ -> false
 
+let writable_dir path =
+  try
+    let file = path ^ "/prova_matita" in
+    let oc = open_out file in
+    close_out oc;
+    Sys.remove file;
+    true
+  with Sys_error _ -> false
+
+
 let is_regular fname =
   try
     (Unix.stat fname).Unix.st_kind = Unix.S_REG