+<p><a href="http://www.gnu.org/licenses/gpl-3.0.txt"><img src="https://img.shields.io/badge/license-GPL_3-green.svg" alt="License GPL 3" /></a>
+<a href="http://melpa.org/#/async"><img src="http://melpa.org/packages/async-badge.svg" alt="MELPA" title="" /></a>
+<a href="http://stable.melpa.org/#/async"><img src="http://stable.melpa.org/packages/async-badge.svg" alt="MELPA Stable" title="" /></a></p>
+
+
# emacs-async
-Adds the ability to process Lisp concurrently, with a very simple syntax:
+`async.el` is a module for doing asynchronous processing in Emacs.
+
+# Install
+
+## Install dired-async
+
+Add to your `.emacs.el`:
+
+ (autoload 'dired-async-mode "dired-async.el" nil t)
+ (dired-async-mode 1)
+
+This will allow you to run asynchronously
+the dired commands for copying, renaming and symlinking.
+If you are a [helm](https://github.com/emacs-helm/helm) user, this will allow you
+to copy, rename etc... asynchronously from [helm](https://github.com/emacs-helm/helm).
+Note that with [helm](https://github.com/emacs-helm/helm)
+you can disable this by running the copy, rename etc... commands with a prefix argument.
+
+If you don't want to make dired/helm asynchronous disable it with `dired-async-mode`.
+
+### Debian and Ubuntu
+
+Users of Debian 9 or later or Ubuntu 16.04 or later may simply `apt-get install elpa-async`.
+
+## Enable asynchronous compilation of your (M)elpa packages
+
+By default emacs package.el compile packages in its running emacs session.
+This is not a problem when installing a new package (which is not actually loaded in current emacs)
+but it may create errors and bad compilation when upgrading a package (old version of package is already loaded
+and running in current emacs).
+You can remedy to this by allowing async to compile your packages asynchronously,
+(helm and magit actually do this by default,
+so if you are using these packages they will compile asynchronously)
+to do this, add to your init file:
+
+ (async-bytecomp-package-mode 1)
+
+
+You can control which packages will compile async with `async-bytecomp-allowed-packages`.
+Set it to `'(all)` to be sure you will compile all packages asynchronously.
+
+# Usage
+
+The interface is intended to be very easy to use:
+
+## async-start
+
+ async-start START-FUNC FINISH-FUNC
+
+Execute START-FUNC (often a lambda) in a subordinate Emacs process. When
+done, the return value is passed to FINISH-FUNC. Example:
(async-start
;; What to do in the child process
(lambda (result)
(message "Async process done, result should be 222: %s" result)))
-If you omit the callback function, `async-start` will return a process object
-that you can `async-get` on when you're ready to wait for the result value:
+If FINISH-FUNC is `nil` or missing, a future is returned that can be inspected
+using `async-get`, blocking until the value is ready. Example:
(let ((proc (async-start
;; What to do in the child process
(message "This is a test")
(sleep-for 3)
222))))
- (message "I'm going to do some work here")
- ;; ....
- (message "Async process done, result should be 222: %s"
+
+ (message "I'm going to do some work here") ;; ....
+
+ (message "Waiting on async process, result should be 222: %s"
(async-get proc)))
+
+If you don't want to use a callback, and you don't care about any return value
+from the child process, pass the `'ignore` symbol as the second argument (if
+you don't, and never call `async-get`, it will leave ``*emacs*`` process buffers
+hanging around):
+
+ (async-start
+ (lambda ()
+ (delete-file "a remote file on a slow link" nil))
+ 'ignore)
+
+Note: Even when FINISH-FUNC is present, a future is still returned except that
+it yields no value (since the value is passed to FINISH-FUNC). Calling
+`async-get` on such a future always returns `nil`. It can still be useful,
+however, as an argument to `async-ready` or `async-wait`.
+
+## async-start-process
+
+ async-start-process NAME PROGRAM FINISH-FUNC &rest PROGRAM-ARGS
+
+Start the executable PROGRAM asynchronously. See `async-start`. PROGRAM is
+passed PROGRAM-ARGS, calling FINISH-FUNC with the process object when done.
+If FINISH-FUNC is `nil`, the future object will return the process object when
+the program is finished. Set DEFAULT-DIRECTORY to change PROGRAM's current
+working directory.
+
+## async-get
+
+ async-get FUTURE
+
+Get the value from an asynchronously called function when it is ready. FUTURE is
+returned by `async-start` or `async-start-process` when its FINISH-FUNC is
+`nil`.
+
+## async-ready
+
+ async-ready FUTURE
+
+Query a FUTURE to see if its function's value is ready -- i.e., if no blocking
+would result from a call to `async-get` on that FUTURE.
+
+## async-wait
+
+ async-wait FUTURE
+
+Wait for FUTURE to become ready.
+
+## async-inject-variables
+
+ async-inject-variables INCLUDE-REGEXP &optional PREDICATE EXCLUDE-REGEXP
+
+Return a `setq` form that replicates part of the calling environment. It sets
+the value for every variable matching INCLUDE-REGEXP and also PREDICATE. It
+will not perform injection for any variable matching EXCLUDE-REGEXP (if
+present). It is intended to be used as follows:
+
+ (async-start
+ `(lambda ()
+ (require 'smtpmail)
+ (with-temp-buffer
+ (insert ,(buffer-substring-no-properties (point-min) (point-max)))
+ ;; Pass in the variable environment for smtpmail
+ ,(async-inject-variables "\\`\\(smtpmail\\|\\(user-\\)?mail\\)-")
+ (smtpmail-send-it)))
+ 'ignore)