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#lang racket/base
;; based on handin-server/private/reloadable
(require syntax/moddep)
(provide reload-module)
(define (reload-module modspec path [notifier #f])
;; the path argument is not needed (could use resolve-module-path here), but
;; its always known when this function is called
(let* ([name ((current-module-name-resolver) modspec #f #f)])
(when notifier (notifier "(re)loading module from ~a" modspec))
(parameterize ([current-module-declare-name name]
[compile-enforce-module-constants #f])
;; only notify, it's fine to reset the file timer, since there's no point
;; in attempting to reload it yet again until it is edited.
(with-handlers ([exn?
(lambda (e)
(notifier "error, module not reloaded (~a)"
(exn-message e))
(notifier "~a~%" (continuation-mark-set->context (exn-continuation-marks e))))])
(namespace-require '(only scheme module #%top-interaction))
(load/use-compiled path)))))
;; pulls out a value from a module, reloading the module if its source file was
;; modified
(provide auto-reload-value)
(define module-times (make-hash))
(define (auto-reload-value modspec valname)
(let* ([path (resolve-module-path modspec #f)]
[last (hash-ref module-times path #f)]
[cur (file-or-directory-modify-seconds path)])
(unless (equal? cur last)
(hash-set! module-times path cur)
(reload-module modspec path))
(dynamic-require modspec valname)))
(define poll-freq 2000.0) ; poll at most once every two seconds
;; pulls out a procedure from a module, and returns a wrapped procedure that
;; automatically reloads the module if the file was changed whenever the
;; procedure is used
(provide auto-reload-procedure)
(define (auto-reload-procedure
modspec procname #:notifier [notifier #f] #:on-reload [on-reload #f])
(let ([path (resolve-module-path modspec #f)] [date #f] [proc #f] [poll #f])
(define (reload)
(unless (and proc (< (- (current-inexact-milliseconds) poll) poll-freq))
(set! poll (current-inexact-milliseconds))
(let ([cur (file-or-directory-modify-seconds path)])
(unless (equal? cur date)
(when on-reload (on-reload))
(set! date cur)
(reload-module modspec path notifier)
(set! proc (dynamic-require modspec procname))))))
(reload)
(lambda xs (reload) (apply proc xs))))
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