-- | An expression on signals
data SignalExpr =
EqLit SignalId String -- ^ Is the given signal equal to the given (VHDL) literal
- | Literal String -- ^ A literal value
+ | Literal String (Maybe Type.Type)-- ^ A literal value, with an optional type to cast to
| Eq SignalId SignalId -- ^ A comparison between to signals
deriving (Show, Eq)
+-- Instantiate Eq for Type, so we can derive Eq for SignalExpr.
+instance Eq Type.Type where
+ (==) = Type.coreEqType
+
-- | Which signals are used by the given SignalExpr?
sigExprUses :: SignalExpr -> [SignalId]
sigExprUses (EqLit id _) = [id]
-sigExprUses (Literal _) = []
+sigExprUses (Literal _ _) = []
sigExprUses (Eq a b) = [a, b]
-- Returns the function used by the given SigDef, if any