Define the abstract syntax of MiniLogo expressions by defining the Haskell data type Expr. You should not include the grouping production in your abstract syntax since it is not needed (see the language description). I have provided the type synonym for variable names. You can use the built-in type Int for the int syntactic category directly.

module HW3 where import Data.List (intercalate) Part 1: Expressions Syntax | Variable names. type Var = String | Expressions. data Expr ExprTODO -- This is a dummy constructor that should be removed! deriving (Eq, Show) | 2 + 3 * x expr1 :: Expr expr1 = undefined -- | 2 + 3 * x + 4 expr2 :: Expr expr2 = undefined | (x + 2) * 3 * y expr3 :: Expr expr3 = undefined -- | (x + 2) * (y + 3) expr4 :: Expr expr4 = undefined module HW3 where import Data.List (intercalate) Part 1: Expressions Syntax | Variable names. type Var = String | Expressions. data Expr ExprTODO -- This is a dummy constructor that should be removed! deriving (Eq, Show) | 2 + 3 * x expr1 :: Expr expr1 = undefined -- | 2 + 3 * x + 4 expr2 :: Expr expr2 = undefined | (x + 2) * 3 * y expr3 :: Expr expr3 = undefined -- | (x + 2) * (y + 3) expr4 :: Expr expr4 = undefined