bind-pull.rkt

#lang racket

;; not working
(module not-working racket
  (define-for-syntax b (box #f))

  (define-syntax (pull stx) (unbox b))

  (define-syntax (bind stx)
    (syntax-case stx ()
      [(_ i body)
       (begin (set-box! b #'i)
              #'(lambda (i) body))]))

  (bind x (pull)))

;; working
(module working racket
  (define-for-syntax b (box #f))
  (define-syntax (pull stx) (unbox b))

  (define-syntax (bind stx)
    (syntax-case stx ()
      [(_ i body)
       #'(lambda (i) (with-id i body))]))

  (define-syntax (with-id stx)
    (syntax-case stx ()
      [(_ i body) (begin (set-box! b #'i) #'body)]))

  (bind x (pull)))