ce?
                    (hashq-set! (module-replacements public-i) external-name #t))
                  (module-add! public-i external-name var)))
              names)))

(define (module-replace! m names)
  (module-export! m names #:replace? #t))

(define (module-export-all! mod)
  "Export all local variables from a module."
  (define (fresh-interface!)
    (let ((iface (make-module)))
      (set-module-name! iface (module-name mod))
      (set-module-version! iface (module-version mod))
      (set-module-kind! iface 'interface)
      (set-module-public-interface! mod iface)
      iface))
  (let ((iface (or (module-public-interface mod)
                   (fresh-interface!))))
    (set-module-obarray! iface (module-obarray mod))))

(define* (module-re-export! m names #:key replace?)
  "Re-export an imported variable."
  (let ((public-i (module-public-interface m)))
    (for-each
     (lambda (name)
       (let* ((internal-name (if (pair? name) (car name) name))
              (external-name (if (pair? name) (cdr name) name))
              (var (module-variable m internal-name)))
         (cond
          ((not var)
           (error "Undefined variable:" internal-name))
          ((eq? var (module-local-variable m internal-name))
           (error "re-exporting local variable:" internal-name))
          (else
           (when replace?
             (hashq-set! (module-replacements public-i) external-name #t))
           (module-add! public-i external-name var)))))
     names)))

(define-syntax-rule (export name ...)
  (eval-when (expand load eval)
    (call-with-deferred-observers
     (lambda ()
       (module-export! (current-module) '(name ...))))))

(define-syntax-rule (re-export name ...)
  (eval-when (expand load eval)
    (call-with-deferred-observers
     (lambda ()
       (module-re-export! (current-module) '(name ...))))))

(define-syntax-rule (export! name ...)
  (eval-when (expand load eval)
    (call-with-deferred-observers
     (lambda ()
       (module-replace! (current-module) '(name ...))))))

(define-syntax-rule (export-syntax name ...)
  (export name ...))

(define-syntax-rule (re-export-syntax name ...)
  (re-export name ...))