X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;ds=sidebyside;f=helm%2Focaml%2Fmathql%2FmQueryUtil.ml;fp=helm%2Focaml%2Fmathql%2FmQueryUtil.ml;h=349c2ac55038f6071aea89ddcddc8fddf1d346b1;hb=1c7fb836e2af4f2f3d18afd0396701f2094265ff;hp=3b16bb6b046d22a383b9c2f6bd03b5190a7dc6ed;hpb=2122459392680c4b53e32a2cf1d4792405f118ce;p=helm.git

diff --git a/helm/ocaml/mathql/mQueryUtil.ml b/helm/ocaml/mathql/mQueryUtil.ml
index 3b16bb6b0..349c2ac55 100644
--- a/helm/ocaml/mathql/mQueryUtil.ml
+++ b/helm/ocaml/mathql/mQueryUtil.ml
@@ -152,7 +152,6 @@ let text_of_query out x sep =
       | M.StatQuery x        -> out "stat "; txt_set x
       | M.Keep b l x         -> out "keep "; txt_allbut b; txt_path_list l;
                                 txt_set x
-
    in 
    txt_set x; out sep
 
@@ -187,6 +186,36 @@ let stop_time (s0, u0) =
    let u1 = Unix.time () in
    Printf.sprintf "%.2fs,%.2fs" (s1 -. s0) (u1 -. u0)
 
+(* operations on lists  *****************************************************)
+
+type 'a comparison = Lt 
+                   | Gt
+		   | Eq of 'a
+
+let list_join f l1 l2 =
+   let rec aux = function
+      | [], v
+      | v, []                                  -> v 
+      | ((h1 :: t1) as v1), ((h2 :: t2) as v2) -> begin
+         match f h1 h2 with
+	    | Lt   -> h1 :: aux (t1, v2)
+	    | Gt   -> h2 :: aux (v1, t2)
+            | Eq h -> h  :: aux (t1, t2)
+         end
+   in aux (l1, l2)
+
+let list_meet f l1 l2 =
+   let rec aux = function
+      | [], v
+      | v, []                                  -> [] 
+      | ((h1 :: t1) as v1), ((h2 :: t2) as v2) -> begin
+         match f h1 h2 with
+	    | Lt   -> aux (t1, v2)
+	    | Gt   -> aux (v1, t2)
+            | Eq h -> h :: aux (t1, t2)
+         end
+   in aux (l1, l2)
+
 (* conversion functions *****************************************************)
 
 type uriref = UriManager.uri * (int list)