kqueue watcher in gerbil scheme

watcher.ss

#!/usr/bin/env gxi
(import 
  :std/format
  :std/os/fcntl
	:std/os/fdio
	:std/os/fd)

(require bsd) (import :std/os/kqueue)

(define observed (make-hash-table-eqv))

; https://stackoverflow.com/questions/19897897/kqueue-only-works-for-folder-path
; https://github.com/vyzo/gerbil/blob/master/src/std/os/kqueue.ss

; Add support for folder
; Add callback support
(def (watch (file "server.ss"))
  (define kq (kqueue))
  (define path (path-normalize file))
  (printf "Watching ~a\n" file)
  (define fd (open path O_RDONLY))
  (hash-put! observed (fd-e fd) file)
  (kqueue-kevent-add kq fd EVFILT_VNODE EV_CLEAR (##fxior NOTE_WRITE NOTE_DELETE))
  (printf "fd ~a\n" fd)
  (defconst nevents 4)
  (def events (make-kevents nevents))
  (let wait-loop ()
    (let (n (kqueue-poll kq events nevents))
      (when (##fxpositive? n)
        (let (event-count n)
          (let event-loop ((i 0))
            (when (fx< i event-count)
              (printf "- ~a\n" (hash-get observed (kevent-ident events i)))
              (event-loop (fx1+ i))))
              )))
    (wait-loop)
  )
)

(watch)