X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fcomponents%2Fbinaries%2Fmatex%2Fground.ml;h=7eebedb7d13e8fa810c4dc0eb867aa038362e474;hb=e880d6eab5e1700f4a625ddcd7d0fa8f0cce2dcc;hp=0e9f28c55bb0578b95f89f8e96957b508b26dd65;hpb=2fa001c86e37c76c840122655cb4ffba8bb30cad;p=helm.git

diff --git a/matita/components/binaries/matex/ground.ml b/matita/components/binaries/matex/ground.ml
index 0e9f28c55..7eebedb7d 100644
--- a/matita/components/binaries/matex/ground.ml
+++ b/matita/components/binaries/matex/ground.ml
@@ -48,10 +48,21 @@ let rec foldi_left mapi i a = function
    | []       -> a
    | hd :: tl -> foldi_left mapi (succ i) (mapi i a hd) tl
 
+let rec rev_mapi mapi i l =
+   let map i a hd = mapi i hd :: a in
+   foldi_left map i [] l
+
 let rec rev_map_append map l r = match l with
    | []       -> r
    | hd :: tl -> rev_map_append map tl (map hd :: r)
 
+let rec split_at x = function
+   | l when x <= 0 -> [], l
+   | []       -> [], []
+   | hd :: tl -> 
+      let l1, l2 = split_at (pred x) tl in
+      hd :: l1, l2
+
 let error s = raise (Error s)
 
 let log s = P.eprintf "MaTeX: %s\n%!" s