#lang plai
;; login : <YOUR-LOGIN-HERE>

(define-type Binding
  [binding (name symbol?) (named-expr CFWAE?)])

(define-type CFWAE
  [num (n number?)]
  [binop (op procedure?) (lhs CFWAE?) (rhs CFWAE?)]
  [with (lob (listof Binding?)) (body CFWAE?)]
  [id (name symbol?)]
  [if0 (c CFWAE?) (t CFWAE?) (e CFWAE?)]
  [fun (args (listof symbol?)) (body CFWAE?)]
  [app (f CFWAE?) (args (listof CFWAE?))])

(define-type Env
  [mtEnv]
  [anEnv (name symbol?) (value CFWAE-Value?) (env Env?)])

(define-type CFWAE-Value
  [numV (n number?)]
  [closureV (params (listof symbol?))
            (body CFWAE?)
            (env Env?)])

;; parse : expression -> CFWAE
; This procedure parses an expression into a CFWAE
(define (parse sexp)
  (...))

;; interp : CFWAE -> CFWAE-Value
;; This procedure evaluates a CFWAE expression, producing a CFWAE-Value.
(define (interp expr)
  (...))