lc.ml

type term = Var of string | Lam of string * term | App of term * term
type value = Closure of ((string * value) list * string * term)

let rec eval env term =
  match term with
  | Var var -> List.assoc var env
  | Lam (param, body) -> Closure (env, param, body)
  | App (lambda, argument) -> (
      let lambda = eval env lambda in
      let argument = eval env argument in
      match lambda with
      | Closure (env, param, body) ->
          let env = (param, argument) :: env in
          eval env body)