Add some comments.

[matthijs/master-project/cλash.git] / cλash / CLasH / VHDL / VHDLTools.hs

diff --git a/cλash/CLasH/VHDL/VHDLTools.hs b/cλash/CLasH/VHDL/VHDLTools.hs
index 8b963f53ed3415885649b50bd09633693f4c927d..2dd0a48edcd397f8cfcc9e2f37adfe1f7f26dcdd 100644 (file)
--- a/cλash/CLasH/VHDL/VHDLTools.hs
+++ b/cλash/CLasH/VHDL/VHDLTools.hs
@@ -304,6 +304,8 @@ isReprType ty = do
     Left _ -> False
     Right _ -> True
 
+-- | Turn a Core type into a HType, returning an error using the given
+-- error string if the type was not representable.
 mkHType :: (TypedThing t, Outputable.Outputable t) => 
   String -> t -> TypeSession HType
 mkHType msg ty = do
@@ -312,6 +314,8 @@ mkHType msg ty = do
     Right htype -> return htype
     Left err -> error $ msg ++ err  
 
+-- | Turn a Core type into a HType. Returns either an error message if
+-- the type was not representable, or the HType generated.
 mkHTypeEither :: (TypedThing t, Outputable.Outputable t) => 
   t -> TypeSession (Either String HType)
 mkHTypeEither tything =
@@ -486,6 +490,7 @@ mkVectorTy (VecType len elHType) = do
           mapM_ (\(id, subprog) -> MonadState.modify tsTypeFuns $ Map.insert (UVecType elHType, id) ((mkVHDLExtId id), subprog)) vecShowFuns
           let ty_def = AST.SubtypeIn vec_id (Just range)
           return (Just (ty_id, Just $ Right ty_def))
+    -- Vector of empty elements becomes empty itself.
     Nothing -> return Nothing
 mkVectorTy htype = error $ "\nVHDLTools.mkVectorTy: Called for HType that is not a VecType: " ++ show htype
 
@@ -531,9 +536,10 @@ getFieldLabels ty = do
   -- Assume the type for which we want labels is really translatable
   htype <- mkHType error_msg ty
   case Map.lookup htype types of
-    Just (Just (_, Just (Left (AST.TDR (AST.RecordTypeDef elems))))) -> return $ map (\(AST.ElementDec id _) -> id) elems
+    Nothing -> error $ "\nVHDLTools.getFieldLabels: Type not found? This should not happen!\nLooking for type: " ++ (pprString ty) ++ "\nhtype: " ++ (show htype) 
     Just Nothing -> return [] -- The type is empty
-    _ -> error $ "\nVHDL.getFieldLabels: Type not found or not a record type? This should not happen! Type: " ++ (show htype)
+    Just (Just (_, Just (Left (AST.TDR (AST.RecordTypeDef elems))))) -> return $ map (\(AST.ElementDec id _) -> id) elems
+    Just (Just (_, Just vty)) -> error $ "\nVHDLTools.getFieldLabels: Type not a record type? This should not happen!\nLooking for type: " ++ pprString (ty) ++ "\nhtype: " ++ (show htype) ++ "\nFound type: " ++ (show vty)
     
 mktydecl :: (AST.VHDLId, Maybe (Either AST.TypeDef AST.SubtypeIn)) -> Maybe AST.PackageDecItem
 mytydecl (_, Nothing) = Nothing