--- | A flattened function application
-data FApp sigid = FApp {
- appFunc :: HsFunction,
- appArgs :: [SignalMap sigid],
- appRes :: SignalMap sigid
-} deriving (Show, Eq)
-
--- | A conditional signal definition
-data CondDef sigid = CondDef {
- cond :: sigid,
- high :: sigid,
- low :: sigid,
- condRes :: sigid
-} deriving (Show, Eq)
+-- | Something that defines a signal
+data SigDef =
+ -- | A flattened function application
+ FApp {
+ appFunc :: HsFunction,
+ appArgs :: [SignalMap],
+ appRes :: SignalMap
+ }
+ -- | A conditional signal definition
+ | CondDef {
+ cond :: SignalId,
+ high :: SignalId,
+ low :: SignalId,
+ condRes :: SignalId
+ }
+ -- | Unconditional signal definition
+ | UncondDef {
+ defSrc :: Either SignalId SignalExpr,
+ defDst :: SignalId
+ } deriving (Show, Eq)
+
+-- | An expression on signals
+data SignalExpr =
+ EqLit SignalId String -- ^ Is the given signal equal to the given (VHDL) literal
+ | Literal String -- ^ A literal value
+ | Eq SignalId SignalId -- ^ A comparison between to signals
+ deriving (Show, Eq)
+
+-- Returns the function used by the given SigDef, if any
+usedHsFunc :: SigDef -> Maybe HsFunction
+usedHsFunc (FApp hsfunc _ _) = Just hsfunc
+usedHsFunc _ = Nothing