constInt :: Parser E.Expr
constInt = 
    do
        n <- token number
        return $ E.Const (E.IntV n)
constInt :: Parser E.Expr
constInt = 
    do
        n <- token number
        return $ E.Const (E.IntV n)
constInt = 
    do
        n <- token number
        return $ E.Const (E.IntV n)