cgen :: S.Expr -> Codegen AST.Operand
--cgen a | trace ("cgen " ++ show a) False = undefined
cgen (S.UnaryOp op a) = do
  cgen $ S.Call ("unary" ++ op) [a]
cgen :: S.Expr -> Codegen AST.Operand
cgen (S.UnaryOp op a) = do
  cgen $ S.Call ("unary" ++ op) [a]
cgen (S.UnaryOp op a) = do
  cgen $ S.Call ("unary" ++ op) [a]