- Level-1: some fixes to the extraction procedure

[helm.git] / components / tactics / proofEngineHelpers.ml

diff --git a/components/tactics/proofEngineHelpers.ml b/components/tactics/proofEngineHelpers.ml
index cf7df2d58a197ca9895837e784aa0a94e4b47294..6e7b5a8e74aa90deb24642ad3184f562233b18fb 100644 (file)
--- a/components/tactics/proofEngineHelpers.ml
+++ b/components/tactics/proofEngineHelpers.ml
@@ -686,3 +686,30 @@ let lookup_type metasenv context hyp =
       | [] -> raise (ProofEngineTypes.Fail (lazy "lookup_type: not premise in the current goal"))
    in
    aux 1 context
+
+(* FG: **********************************************************************)
+
+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 get_name context index =
+   try match List.nth context (pred index) with
+      | Some (Cic.Name name, _)     -> Some name
+      | _                           -> None
+   with Invalid_argument "List.nth" -> None
+
+let get_rel context name =
+   let rec aux i = function
+      | []                                      -> None
+      | Some (Cic.Name s, _) :: _ when s = name -> Some (Cic.Rel i)
+      | _ :: tl                                 -> aux (succ i) tl
+   in
+   aux 1 context