X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;ds=sidebyside;f=matita%2Fcomponents%2Fbinaries%2Fmatex%2Fground.ml;h=7eebedb7d13e8fa810c4dc0eb867aa038362e474;hb=50a9ed8c6207145fccf59e6a5dbbff935cd2c6d7;hp=c24162ae0e3e47c2cf950a312407d61929be4413;hpb=788e7cb15734fd228e8788ea628934af483ae772;p=helm.git

diff --git a/matita/components/binaries/matex/ground.ml b/matita/components/binaries/matex/ground.ml
index c24162ae0..7eebedb7d 100644
--- a/matita/components/binaries/matex/ground.ml
+++ b/matita/components/binaries/matex/ground.ml
@@ -19,6 +19,8 @@ exception Error of string
 
 let id x = x
 
+let id2 x y = x, y 
+
 let rec segments_of_string ss l s =
    match try Some (S.index s '/') with Not_found -> None with
       | None   -> s :: ss
@@ -46,10 +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