added more manual tests

test_program

@@ -1,23 +1,24 @@
--- data Bool () where {
---     True : Bool ()
---     False : Bool ()
--- };
-
 data Maybe ('a) where {
     Nothing : Maybe ('a)
     Just : 'a -> Maybe ('a)
 };
 
--- main : Bool () -> Maybe (Bool ()) ;
--- main x =
---     case x of {
---         True => Nothing;
---         False => Just True
---     };
-
-fun : Maybe ('a) -> 'a ;
-fun a =
+fromJust : Maybe ('a) -> 'a ;
+fromJust a =
     case a of {
-        Just c => c
+        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
+    }