deque-blog/dsl_arithmetic_3_expr.hs

## dsl_arithmetic_3_expr.hs
{-# LANGUAGE DeriveFunctor, DeriveFoldable, DeriveTraversable #-}

data OpType = Add | Mul deriving (Show, Eq, Ord)

data ExprR r
  = Cst Int
  | Var Id
  | Op OpType [r]
  deriving (Show, Eq, Ord, Functor, Foldable, Traversable)
	{-# LANGUAGE DeriveFunctor, DeriveFoldable, DeriveTraversable #-}

	data OpType = Add \| Mul deriving (Show, Eq, Ord)

	data ExprR r
	= Cst Int
	\| Var Id
	\| Op OpType [r]
	deriving (Show, Eq, Ord, Functor, Foldable, Traversable)