From: Ted Zlatanov <tzz@lifelogs.com>
To: emacs-devel@gnu.org
Subject: Re: ELisp futures and continuations/coroutines
Date: Fri, 20 May 2011 10:29:39 -0500 [thread overview]
Message-ID: <8739k9s84c.fsf@lifelogs.com> (raw)
In-Reply-To: 87d3jew4eq.fsf@ambire.localdomain
On Fri, 20 May 2011 03:23:57 +0200 Thien-Thi Nguyen <ttn@gnuvola.org> wrote:
TN> () Ted Zlatanov <tzz@lifelogs.com>
TN> () Thu, 19 May 2011 18:48:49 -0500
TN> Why tie futures to fsm.el or deferred.el specifically? That seems like
TN> an implementation detail.
TN> Well, one important detail, whether you consider it implementation
TN> or design, is who kicks the evaluation (and when). In the case of
TN> fsm.el, this is done by either a timer or from process input.
Yes, but deferred.el does it with a timer-triggered queue drain, storing
the next deferred item in the current one, and the concurrency branch
might do it with a separate thread. These implementation details
obscure the purpose of the "future" type: to hold a potential value.
TN> A "future type" w/o this detail well-defined is no better than
TN> a simple closure (IMHO) because it has no concept of time / timing.
...
TN> Minimalism is nice, but i suppose i like a more full-featured "future type",
TN> one that can self-terminate, for example. Conniving computers, grumble...
TN> (i'll have to dig up and post some old fsm toys -- get a dozen of them going
TN> at once and you'll see what i mean :-D).
Why should a future type encapsulate any time knowledge? The whole
point is that you don't know when and if it will be available.
You could derive a expected-future which will have some knowledge of
when it might have the data. A self-managed-future could run its own
functions. And so on. But I really want a clean, simple API that can
be used by any library.
Let's get this done, simple though it is, and then see how it will
integrate with fsm.el and deferred.el. I really think it will benefit
everyone to start simple.
TN> Yes, [defstruct is] much cleaner than fsm's plist munging, but (as i
TN> tried to express above), that is just the shape of the sail and not
TN> the motion of the boat.
Heh heh. I guess we're close to land then.
TN> Keep going!
The below adds a way to cancel a future. I think error handling is all
that's left unsaid.
Ted
#+begin_src lisp
(defstruct future callback errorback status value)
(defun future-done-p (future)
(future-status future))
(defun future-errored-p (future)
(eq (future-status future) 'error))
(defun future-cancelled-p (future)
(eq (future-status future) 'cancel))
(defun future-finish (future &optional status)
(unless (future-done-p future)
(setf (future-status future) (or status t))
(when (future-callback future)
(funcall (future-callback future) future))))
(defun future-errored (future error)
(unless (future-done-p future)
(setf (future-status future) 'error)
(when (future-errorback future)
(funcall (future-errorback future) future error))))
(defun future-call (future)
(unless (future-done-p future)
(let ((ff (future-value future)))
(when (functionp ff)
;; TODO: needs error handling
(setf (future-value future)
(funcall ff))))
(future-finish future)))
(defun future-cancel (future)
(unless (future-done-p future)
(future-finish future 'cancel)))
#+end_src
next prev parent reply other threads:[~2011-05-20 15:29 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-14 10:32 more url-utils? joakim
2011-05-14 11:21 ` Lars Magne Ingebrigtsen
2011-05-14 11:42 ` joakim
2011-05-15 1:59 ` Lars Magne Ingebrigtsen
2011-05-14 20:42 ` Dimitri Fontaine
2011-05-15 14:26 ` Jason Rumney
2011-05-16 18:25 ` Ted Zlatanov
2011-05-16 19:03 ` Stefan Monnier
2011-05-16 19:17 ` Ted Zlatanov
2011-05-16 19:22 ` Lennart Borgman
2011-05-16 19:32 ` Ted Zlatanov
2011-05-16 19:33 ` Lennart Borgman
2011-05-16 19:55 ` Ted Zlatanov
2011-05-16 19:52 ` Julien Danjou
2011-05-16 20:18 ` Ted Zlatanov
2011-05-17 3:04 ` Stefan Monnier
2011-05-17 8:13 ` Julien Danjou
2011-05-16 19:53 ` Stefan Monnier
2011-05-16 21:07 ` joakim
2011-05-16 21:18 ` Ted Zlatanov
2011-05-16 21:21 ` Lennart Borgman
2011-05-16 21:58 ` joakim
2011-05-17 11:40 ` Lars Magne Ingebrigtsen
2011-05-17 13:34 ` Stefan Monnier
2011-05-14 13:21 ` Ted Zlatanov
2011-05-16 13:15 ` Stefan Monnier
2011-05-16 15:19 ` Tom Tromey
2011-05-16 15:45 ` Stefan Monnier
2011-05-16 17:04 ` joakim
2011-05-16 17:17 ` Lennart Borgman
2011-05-16 17:30 ` Stefan Monnier
2011-05-16 18:39 ` Julien Danjou
2011-05-15 13:34 ` Chong Yidong
2011-05-17 22:26 ` Ted Zlatanov
2011-05-18 0:11 ` Stefan Monnier
2011-05-18 2:14 ` Ted Zlatanov
2011-05-18 12:16 ` Stefan Monnier
2011-05-18 13:44 ` Ted Zlatanov
2011-05-18 14:09 ` Stefan Monnier
2011-05-18 14:43 ` Ted Zlatanov
2011-05-18 22:05 ` Stefan Monnier
2011-05-19 1:57 ` Ted Zlatanov
2011-05-19 2:28 ` Stefan Monnier
2011-05-19 10:28 ` Ted Zlatanov
2011-05-19 11:53 ` Stefan Monnier
2011-05-19 12:43 ` Ted Zlatanov
2011-05-19 13:28 ` Stefan Monnier
2011-05-19 13:35 ` Ted Zlatanov
2011-05-30 17:31 ` Lars Magne Ingebrigtsen
2011-05-30 19:09 ` Stefan Monnier
2011-05-30 19:38 ` Lars Magne Ingebrigtsen
2011-05-30 22:17 ` Stefan Monnier
2011-05-30 23:11 ` Lars Magne Ingebrigtsen
2011-05-31 1:26 ` Stefan Monnier
2011-05-31 10:15 ` Lars Magne Ingebrigtsen
2011-05-31 12:45 ` Stefan Monnier
2011-05-31 18:38 ` Lars Magne Ingebrigtsen
2011-05-19 14:11 ` joakim
2011-05-19 14:40 ` Stefan Monnier
2011-05-19 13:46 ` ELisp futures and continuations/coroutines (was: more url-utils?) Ted Zlatanov
2011-05-19 14:15 ` ELisp futures and continuations/coroutines Stefan Monnier
2011-05-19 14:16 ` joakim
2011-05-19 15:24 ` Ted Zlatanov
2011-05-19 15:09 ` Thien-Thi Nguyen
2011-05-19 15:31 ` Ted Zlatanov
2011-05-19 16:40 ` Thien-Thi Nguyen
2011-05-19 23:48 ` Ted Zlatanov
2011-05-20 1:23 ` Thien-Thi Nguyen
2011-05-20 4:18 ` Mohsen BANAN
2011-05-20 15:30 ` Ted Zlatanov
2011-05-20 15:29 ` Ted Zlatanov [this message]
2011-05-22 13:17 ` Thien-Thi Nguyen
2011-05-23 14:24 ` Ted Zlatanov
2011-05-23 14:59 ` Stefan Monnier
2011-05-23 15:10 ` Ted Zlatanov
2011-05-23 15:42 ` SAKURAI Masashi
2011-05-25 2:07 ` Ted Zlatanov
2011-05-26 0:23 ` SAKURAI Masashi
2011-06-03 13:59 ` SAKURAI Masashi
2011-06-03 16:06 ` Ted Zlatanov
2011-06-04 6:21 ` SAKURAI Masashi
2011-06-29 5:31 ` SAKURAI Masashi
2011-06-29 12:01 ` Ted Zlatanov
2011-06-29 17:33 ` SAKURAI Masashi
2011-06-29 16:09 ` Chong Yidong
2011-05-23 15:45 ` Stefan Monnier
2011-05-25 2:02 ` Ted Zlatanov
2011-05-31 10:53 ` Ted Zlatanov
2011-05-31 16:55 ` Ted Zlatanov
2011-05-19 17:03 ` ELisp futures and continuations/coroutines (was: more url-utils?) SAKURAI Masashi
2011-05-19 22:51 ` ELisp futures and continuations/coroutines Ted Zlatanov
2011-05-20 15:49 ` SAKURAI Masashi
2011-05-25 2:17 ` Ted Zlatanov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=8739k9s84c.fsf@lifelogs.com \
--to=tzz@lifelogs.com \
--cc=emacs-devel@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).