improve stmt representation

src/Convert/Foreach.hs

@@ -22,9 +22,9 @@ convertStmt :: Stmt -> Stmt
 convertStmt (Foreach x idxs stmt) =
     (foldl (.) id $ map toLoop $ zip [1..] idxs) stmt
     where
-        toLoop :: (Int, Maybe Identifier) -> (Stmt -> Stmt)
-        toLoop (_, Nothing) = id
-        toLoop (d, Just i) =
+        toLoop :: (Int, Identifier) -> (Stmt -> Stmt)
+        toLoop (_, "") = id
+        toLoop (d, i) =
             For (Left [idxDecl]) cmp [incr]
             where
                 queryFn f = DimFn f (Right $ Ident x) (Number $ show d)

src/Convert/Traverse.hs

@@ -255,14 +255,10 @@ traverseSinglyNestedStmtsM fullMapper = cs
 traverseAssertionStmtsM :: Monad m => MapperM m Stmt -> MapperM m Assertion
 traverseAssertionStmtsM mapper = assertionMapper
     where
-        actionBlockMapper (ActionBlockIf stmt) =
-            mapper stmt >>= return . ActionBlockIf
-        actionBlockMapper (ActionBlockElse Nothing stmt) =
-            mapper stmt >>= return . ActionBlockElse Nothing
-        actionBlockMapper (ActionBlockElse (Just s1) s2) = do
+        actionBlockMapper (ActionBlock s1 s2) = do
             s1' <- mapper s1
             s2' <- mapper s2
-            return $ ActionBlockElse (Just s1') s2'
+            return $ ActionBlock s1' s2'
         assertionMapper (Assert e ab) =
             actionBlockMapper ab >>= return . Assert e
         assertionMapper (Assume e ab) =