+-- Expands the most simple case expression that scrutinizes a plain variable
+-- and has a single alternative. This simple form currently allows only for
+-- unpacking tuple variables.
+expandSingleAltCaseExpr ::
+ [(CoreBndr, SignalNameMap AST.VHDLId)]
+ -- A list of bindings in effect
+ -> Var.Var -- The scrutinee
+ -> CoreBndr -- The binder to bind the scrutinee to
+ -> CoreAlt -- The single alternative
+ -> VHDLState ( [AST.SigDec], [AST.ConcSm], [SignalNameMap AST.VHDLId], SignalNameMap AST.VHDLId)
+ -- See expandExpr
+
+expandSingleAltCaseExpr binds v b alt@(DataAlt datacon, bind_vars, expr) =
+ if not (DataCon.isTupleCon datacon)
+ then
+ error $ "Dataconstructors other than tuple constructors not supported in case pattern of alternative: " ++ (showSDoc $ ppr alt)
+ else
+ let
+ -- Lookup the scrutinee (which must be a variable bound to a tuple) in
+ -- the existing bindings list and get the portname map for each of
+ -- it's elements.
+ Tuple tuple_ports = Maybe.fromMaybe
+ (error $ "Case expression uses unknown scrutinee " ++ getOccString v)
+ (lookup v binds)
+ -- TODO include b in the binds list
+ -- Merge our existing binds with the new binds.
+ binds' = (zip bind_vars tuple_ports) ++ binds
+ in
+ -- Expand the expression with the new binds list
+ expandExpr binds' expr
+
+expandSingleAltCaseExpr _ _ _ alt =
+ error $ "Case patterns other than data constructors not supported in case alternative: " ++ (showSDoc $ ppr alt)
+
+