type binop =
  | Add
  | Sub
  | Mul
  | Div
  | Eq
  | Ne
  | Lt
  | Le
  | Gt
  | Ge
  | And
  | Or

type expr = {
  e : expr_desc;
  espan : Location.span;
}

and expr_desc =
  | EInt of int
  | EBool of bool
  | EString of string
  | EUnit
  | EVar of string
  | ELet of string * expr * expr
  | ELambda of string * expr
  | EApp of expr * expr
  | EIf of expr * expr * expr
  | EBinop of binop * expr * expr
  | ENeg of expr
  | ETuple of expr list
  | ERecord of (string * expr) list
  | EField of expr * string

let make e espan = { e = e; espan = espan }

let binop_name = function
  | Add -> "+"
  | Sub -> "-"
  | Mul -> "*"
  | Div -> "/"
  | Eq -> "="
  | Ne -> "<>"
  | Lt -> "<"
  | Le -> "<="
  | Gt -> ">"
  | Ge -> ">="
  | And -> "&&"
  | Or -> "||"

let string_of_binop = binop_name