type op
  = OpAdd
  | OpSub
  | OpMul
  | OpDiv

type lit
  = LitInt of int64
  | LitFloat of float

type expr
  = ExprLit of lit
  | ExprBin of expr * op * expr

type func =
  { name : string
  }

type decl
  = DeclFunc of func

type program = decl list