jtk-dvlp.async.interop.callback — jtk-dvlp/core.async-helpers 3.0.2

<cb! clj/s macro

(<cb! ?exp)

Like <! for callback based functions via cb->c convertion.

cb->c clj/s macro

(cb->c exp)

(cb->c [f & forms :as _exp] auto-close?)

Creates a chan base on the callbacks of exp. Symbols callback / resolve and reject marks the callback position of exp to put resolutions and rejections onto the new created channel. If no mark is given, assumes resolve position is the last arg of exp and will append it.

exp callbacks must expect only one argument!

Rejections will be used as cause for a new created ExceptionInfo.

Given auto-close? false the caller of cb->c is responsible for closing the channel! Otherwise channel will be closed after first put (resolve or reject).

If calling exp fails an error / exception will be put onto the new created channel with fail information. The channel will be closed then.

Example:

(let [callback-based-fn
      (fn callback-based-fn
        [value-to-carry has-to-fail? success fail]
        (Thread/sleep 1000)
        (if has-to-fail?
          (fail [:nope value-to-carry])
          (success [:yeah value-to-carry])))]

  (go
   (try
     (-> (callback-based-fn
          5 true
          resolve
          ;; fn must be inline so that `cb->c` can recognize `reject` mark!
          (fn modifiy-error-before-reject-it [error]
            (->> {:error error}
                 (ex-info "nix-gut")
                 (reject))))

         (<cb!)
         (println))

     (catch ExceptionInfo e
   (println e)))))