new grammar and adapted renamer

test_program

@@ -1,24 +1,4 @@
-data Maybe ('a) where {
-    Nothing : Maybe ('a)
-    Just : 'a -> Maybe ('a)
-};
-
-fromJust : Maybe ('a) -> 'a ;
-fromJust a =
-    case a of {
-        Just a => a
-    };
-
-fromMaybe : 'a -> Maybe ('a) -> 'a ;
-fromMaybe a b =
-    case b of {
-        Just a => a;
-        Nothing => a
-    };
-
-maybe : 'b -> ('a -> 'b) -> Maybe ('a) -> 'b;
-maybe b f ma =
-    case ma of {
-        Just a => f a;
-        Nothing => b
-    }
+data Maybe (a) where {
+    Nothing : Maybe (a)
+    Just : a -> Maybe (a)
+}