data Entity = Entity {
ent_id :: AST.VHDLId, -- ^ The id of the entity
ent_args :: [Port], -- ^ A port for each non-empty function argument
- ent_res :: Port, -- ^ The output port
+ ent_res :: Maybe Port, -- ^ The output port
ent_dec :: AST.EntityDec -- ^ The complete entity declaration
} deriving (Show);