Make output ports optional.

[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 eabb1b48f371a3a4e0f1c0515b91c97136f94756..36d35e3701c4076273d4e3272c6df8fe7457f0ae 100644 (file)
--- a/cλash/CLasH/VHDL/VHDLTools.hs
+++ b/cλash/CLasH/VHDL/VHDLTools.hs
@@ -90,18 +90,16 @@ mkAssocElems ::
   -> Entity                     -- ^ The entity to map against.
   -> TranslatorSession [AST.AssocElem] -- ^ The resulting port maps
 mkAssocElems args res entity =
-    -- Create the actual AssocElems
-    return $ zipWith mkAssocElem ports sigs
+    return $ arg_maps ++ (Maybe.maybeToList res_map_maybe)
   where
-    -- Turn the ports and signals from a map into a flat list. This works,
-    -- since the maps must have an identical form by definition. TODO: Check
-    -- the similar form?
     arg_ports = ent_args entity
-    res_port  = ent_res entity
-    -- Extract the id part from the (id, type) tuple
-    ports     = map fst (res_port : arg_ports)
-    -- Translate signal numbers into names
-    sigs      = (vhdlNameToVHDLExpr res : args)
+    res_port_maybe = ent_res entity
+    -- Create an expression of res to map against the output port
+    res_expr = vhdlNameToVHDLExpr res
+    -- Map each of the input ports
+    arg_maps = zipWith mkAssocElem (map fst arg_ports) args
+    -- Map the output port, if present
+    res_map_maybe = fmap (\port -> mkAssocElem (fst port) res_expr) res_port_maybe
 
 -- | Create an VHDL port -> signal association
 mkAssocElem :: AST.VHDLId -> AST.Expr -> AST.AssocElem
@@ -728,3 +726,8 @@ mkSigDec bndr = do
   case type_mark_maybe of
     Just type_mark -> return $ Just (AST.SigDec (varToVHDLId bndr) type_mark Nothing)
     Nothing -> return Nothing
+
+-- | Does the given thing have a non-empty type?
+hasNonEmptyType :: (TypedThing t, Outputable.Outputable t) => 
+  t -> TranslatorSession Bool
+hasNonEmptyType thing = MonadState.lift tsType $ isJustM (vhdl_ty "hasNonEmptyType: Non representable type?" thing)