type literal = String of string | Number of float | Bool of bool | Nil
[@@deriving show { with_path = false }]

(* let show_literal literal =
   match literal with
   | String s -> s
   | Number x -> string_of_float x
   | Bool b -> string_of_bool b
   | Nil -> "nil" *)

type binary_op =
  | Plus
  | Minus
  | Mul
  | Div
  | Equal
  | Less
  | Greater
  | LessEqual
  | GreaterEqual
  | And
  | Or
[@@deriving show { with_path = false }]

type unary_op = Neg | Not [@@deriving show { with_path = false }]

type expr =
  | Literal of literal
  | BinaryExpr of { op : binary_op; left : expr_node; right : expr_node }
  | UnaryExpr of { op : unary_op; expr : expr_node }

and expr_node = { expr : expr; pos : Error.code_pos }

let rec show_expr ?(indent = 0) expr =
  let show_indented = show_expr ~indent:(indent + 2) in
  let ident_s = String.make indent ' ' in
  match expr with
  | Literal literal -> ident_s ^ show_literal literal
  | BinaryExpr { op; left; right } ->
      ident_s ^ show_binary_op op ^ "\n" ^ show_indented left.expr ^ "\n" ^ show_indented right.expr
  | UnaryExpr { op; expr } -> ident_s ^ show_unary_op op ^ "\n" ^ show_indented expr.expr

let show_expr_node expr_node = show_expr expr_node.expr
let make_expr_node (pos : Error.code_pos) (expr : expr) = { expr; pos }
let make_string (pos : Error.code_pos) (s : string) = make_expr_node pos (Literal (String s))
let make_number (pos : Error.code_pos) (x : float) = make_expr_node pos (Literal (Number x))
let make_bool (pos : Error.code_pos) (b : bool) = make_expr_node pos (Literal (Bool b))
let make_nil (pos : Error.code_pos) = make_expr_node pos (Literal Nil)

let make_binary (pos : Error.code_pos) (op : binary_op) (left : expr_node) (right : expr_node) =
  make_expr_node pos (BinaryExpr { op; left; right })

let make_unary (pos : Error.code_pos) (op : unary_op) (expr : expr_node) =
  make_expr_node pos (UnaryExpr { op; expr })