Re: GSoC: collaborative editing

[Thien-Thi Nguyen <ttn@gnuvola.org>]

() Brian Templeton <bpt@tunes.org>
() Sat, 11 Apr 2009 16:07:20 -0400

   [introduction]

Sounds interesting.  Have you thought about a peer-to-peer architecture?
I don't know if i'm qualified to be a sponsor, but i wouldn't mind
helping, w/ the caveat that the design move away from requiring a
separate server and towards peer-to-peer.

   1. A precise change reporting mechanism, replacing
      {before,after}-change-functions.  This will require cooperation
      with other Emacs developers and must not reduce performance for
      applications not requiring precise change reporting.

Why must these be replaced?

   2. A transclusion system, which will be used as a test of the new change
      reporting mechanism.

   3. A collaborative editing system using a modified version of the
      Jupiter algorithm, comprising:

      - A client written in Emacs Lisp.
      - A modified version of an existing server written in Erlang.

I think a server written in Emacs Lisp would gain more traction.

   4. End-user documentation, including a user guide published either as
      Texinfo or on the EmacsWiki.

   5. An updated version of the Emacs Lisp manual describing the new change
      reporting mechanism.

   [Plan: discuss change functions and then] debitrot the Erlang server
   and add support for a simple binary protocol in addition to the HTTP
   interface used by the old JS and Flash clients.

Probably you want to avoid binary protocol unless absolutely necessary.
Why not translate the existing protocol to use Emacs-`read'able sexps?

   During the last half of the program I will work on the client itself
   -- implementing the revised Jupiter algorithm, support for the binary
   protocol, a simple interactive client, lists of remote users,
   visualization of the activity of other users (e.g. coloring spans of
   text according to who last edited it, indicating others' point
   positions, etc.), and so on.

Many of these features are supplied by Emacs itself.  Indeed, Emacs is
already a "simple interactive client" of its change-recording internals.

thi