From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Qiantan Hong Newsgroups: gmane.emacs.devel Subject: Re: Question collaborative editing. Date: Wed, 30 Sep 2020 17:00:46 +0000 Message-ID: References: <20200924013655.asv2tem25cbwv5et@Ergus> <2ACED303-9A2C-4363-BE56-2E9AF0B8DC85@posteo.net> <20200925002239.fgg3vw2nylltcoyp@Ergus> <219042AC-556D-48CC-8920-82D9BF2BD3AA@aol.com> <3A81FB67-A558-4281-8285-CDD9B01033E3@posteo.net> <1C949FC9-6023-467E-99EC-75D57B08AFB0@gnu.support> <20200929124513.fd745r2txowwbiir@Ergus> <87blho7af9.fsf@red-bean.com> <20200929215849.zg4wzytbrwx2b7ih@Ergus> <84B86B7C-81F0-42DF-894C-BF577E4B3D6E@mit.edu> <83a6x7js6y.fsf@gnu.org> <83eemji6e8.fsf@gnu.org> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="Apple-Mail=_93E51FD8-8E81-4D7A-AABF-DE46F386301A"; protocol="application/pkcs7-signature"; micalg=sha-256 Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="38219"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Ergus , Fermin , Jean Louis , Noam Postavsky , Emacs developers , Karl Fogel , Stefan Monnier To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Sep 30 19:04:08 2020 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kNfWQ-0009ki-2W for ged-emacs-devel@m.gmane-mx.org; Wed, 30 Sep 2020 19:04:06 +0200 Original-Received: from localhost ([::1]:41090 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kNfWO-0004ox-Lb for ged-emacs-devel@m.gmane-mx.org; Wed, 30 Sep 2020 13:04:04 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:42432) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kNfTa-00031F-4V for emacs-devel@gnu.org; Wed, 30 Sep 2020 13:01:10 -0400 Original-Received: from outgoing-exchange-5.mit.edu ([18.9.28.59]:46296) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kNfTX-0008Dy-2C; Wed, 30 Sep 2020 13:01:09 -0400 Original-Received: from w92exedge4.exchange.mit.edu (W92EXEDGE4.EXCHANGE.MIT.EDU [18.7.73.16]) by outgoing-exchange-5.mit.edu (8.14.7/8.12.4) with ESMTP id 08UH0qLZ026081; Wed, 30 Sep 2020 13:01:01 -0400 Original-Received: from oc11expo16.exchange.mit.edu (18.9.4.47) by w92exedge4.exchange.mit.edu (18.7.73.16) with Microsoft SMTP Server (TLS) id 15.0.1293.2; Wed, 30 Sep 2020 13:00:04 -0400 Original-Received: from oc11expo16.exchange.mit.edu (18.9.4.47) by oc11expo16.exchange.mit.edu (18.9.4.47) with Microsoft SMTP Server (TLS) id 15.0.1365.1; Wed, 30 Sep 2020 13:00:46 -0400 Original-Received: from oc11expo16.exchange.mit.edu ([18.9.4.47]) by oc11expo16.exchange.mit.edu ([18.9.4.47]) with mapi id 15.00.1365.000; Wed, 30 Sep 2020 13:00:46 -0400 Thread-Topic: Question collaborative editing. Thread-Index: AQHWkA+RtV3K1wr9B0aFczVHqkD+n6lzGC2+gAByx1WAA75ZgIABUIuAgAAtCoCAAKrvgIAEEd+AgAGGOACAABFAAIAAe9OAgABIs4CAAA5xVYAAjDuAgAAchYCAAKh2a4AAZX0A///GIeWAAE52AA== In-Reply-To: <83eemji6e8.fsf@gnu.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: yes x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [18.18.245.17] Received-SPF: pass client-ip=18.9.28.59; envelope-from=qhong@mit.edu; helo=outgoing-exchange-5.mit.edu X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/30 13:01:05 X-ACL-Warn: Detected OS = Windows 7 (Websense crawler) X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, HTML_MESSAGE=0.001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:256771 Archived-At: --Apple-Mail=_93E51FD8-8E81-4D7A-AABF-DE46F386301A Content-Type: multipart/alternative; boundary="Apple-Mail=_4EA58A1D-A053-41AA-859A-48BAD3EB4FBF" --Apple-Mail=_4EA58A1D-A053-41AA-859A-48BAD3EB4FBF Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > That's the problem collaborative editing needs to solve, isn't it? > The communications between clients should allow resolution of > differences in buffer position, and detection of losing track of text > modifications. > I don't think I understand what you mean by "C library" here. As discussed above, if we implement CRDT as a =E2=80=9Ceditor agnostic C library=E2=80=9D, then there will likely to be an extra = synchronization between C library and emacs. > The communications between clients should allow resolution of > differences in buffer position, and detection of losing track of text > modifications. I=E2=80=99m talking about synchronization between the buffer data = structure in C library, and buffer data structure in Emacs. Apparently we=E2=80=99re not going to implement CRDT between them (otherwise why not just let Emacs powered CRDT talk to each other), and most likely they will exchange message about raw=20 (buffer position, operation, text). But this is the most naive synchronization mechanism and have no robustness. > You don't need buffer-modification hooks, you can use other existing > mechanisms. Emacs knows that buffer text was changed even if the > modification hooks were inhibited. That=E2=80=99s a workaround, but I=E2=80=99m not sure if it can capture = user intent (i.e. it gives operation-wise information rather than just a diff = between versions of buffer). If it can=E2=80=99t then we will need to implement = both update based on modification-hooks and change state of the buffer, which is an additional impl/maintenance burden.= --Apple-Mail=_4EA58A1D-A053-41AA-859A-48BAD3EB4FBF Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
That's the problem collaborative = editing needs to solve, isn't it?
The communications between clients should allow resolution = of
differences = in buffer position, and detection of losing track of text
modifications.

I don't think I understand what you mean by "C library" = here.

As discussed = above, if we implement CRDT as a =E2=80=9Ceditor agnostic
C = library=E2=80=9D, then there will likely to be an extra = synchronization
between C library and emacs.

The = communications between clients should allow resolution of
differences in buffer position, and detection of losing = track of text
modifications.
I=E2=80=99m talking = about synchronization between the buffer data structure
in C library, and buffer data structure in = Emacs.
Apparently we=E2=80=99re not going to = implement CRDT between them
(otherwise why not = just let Emacs powered CRDT talk to each other),
and most likely they will exchange message about = raw 
(buffer position, operation, text). But = this is the most naive
synchronization mechanism = and have no robustness.

You don't need = buffer-modification hooks, you can use other existing
mechanisms.  Emacs knows that buffer text was changed = even if the
modification hooks were = inhibited.
That=E2=80=99s a workaround, but I=E2=80=99m not = sure if it can capture user intent
(i.e. it gives = operation-wise information rather than just a diff between
versions of buffer). If it can=E2=80=99t then we will need to = implement both
update based on modification-hooks = and change state of the buffer,
which is an = additional impl/maintenance burden.
= --Apple-Mail=_4EA58A1D-A053-41AA-859A-48BAD3EB4FBF-- --Apple-Mail=_93E51FD8-8E81-4D7A-AABF-DE46F386301A Content-Disposition: attachment; filename="smime.p7s" Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCA70w ggO5MIIDIqADAgECAhAaql39NsO1qLVjkS2hl517MA0GCSqGSIb3DQEBCwUAMGwxCzAJBgNVBAYT AlVTMRYwFAYDVQQIEw1NYXNzYWNodXNldHRzMS4wLAYDVQQKEyVNYXNzYWNodXNldHRzIEluc3Rp dHV0ZSBvZiBUZWNobm9sb2d5MRUwEwYDVQQLEwxDbGllbnQgQ0EgdjEwHhcNMjAwODAzMDEyNDIz WhcNMjEwODAxMDEyNDIzWjCBoTELMAkGA1UEBhMCVVMxFjAUBgNVBAgTDU1hc3NhY2h1c2V0dHMx LjAsBgNVBAoTJU1hc3NhY2h1c2V0dHMgSW5zdGl0dXRlIG9mIFRlY2hub2xvZ3kxFTATBgNVBAsT DENsaWVudCBDQSB2MTEVMBMGA1UEAxMMUWlhbnRhbiBIb25nMRwwGgYJKoZIhvcNAQkBFg1xaG9u Z0BNSVQuRURVMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAylUlEQdK4BSXKzoGh6As CKN/TpLmC0kjhPdxUKMj1/86Xl6GDCla4h95uISDOWVAKdu3cIlA8m9zRLT2jNEIkt1DVpXP6c9h y8RRyfJm0qlrvr6tsHi5AmO4Li6s2dEGaTxbakPL6vEn7ZYr86t5orq56nubki77Z8ZvRv9/fWdF bF/YBNGDayLNk0NbXIEQdCHiz1l+bxfw+GHHRmdOge3MKWSg463+GGMdxtLQ61AbtR2vm47FIJBt c0X6ptcInWUg4Nf/9vSNGl6KvREvfbEWKCT6TfL5ncIFlitf6ZWKue2PZ4ULFfIQ3/7EsEk03xxr S7sTOy7e2dbPboe/WwIDAQABo4GhMIGeMAkGA1UdEwQCMAAwEQYJYIZIAYb4QgEBBAQDAgWgMB0G A1UdJQQWMBQGCCsGAQUFBwMEBggrBgEFBQcDAjALBgNVHQ8EBAMCBeAwHQYDVR0OBBYEFDeb9Jlj XSm+y0CD872IhzRDIGv1MDMGA1UdHwQsMCowKKAmoCSGImh0dHA6Ly9jYS5taXQuZWR1L2NhL21p dGNsaWVudC5jcmwwDQYJKoZIhvcNAQELBQADgYEApBTx4tBbD5rQ+bNGd/Z3OBV07qFsm5QHNg0+ 6lxJ3j7q5zMMq35o6y5cBIhcFG6t+MFqJIdERZ3EprDturyqozQsIBMHFnqh+iZcMg0uQyssEqKZ hrzIdw8GuY4Z6jNewdGy5mwwG9yjpEbzWWgdofSM5rnezZz7EvCQu9ilt1sxggNDMIIDPwIBATCB gDBsMQswCQYDVQQGEwJVUzEWMBQGA1UECBMNTWFzc2FjaHVzZXR0czEuMCwGA1UEChMlTWFzc2Fj aHVzZXR0cyBJbnN0aXR1dGUgb2YgVGVjaG5vbG9neTEVMBMGA1UECxMMQ2xpZW50IENBIHYxAhAa ql39NsO1qLVjkS2hl517MA0GCWCGSAFlAwQCAQUAoIIBkzAYBgkqhkiG9w0BCQMxCwYJKoZIhvcN AQcBMBwGCSqGSIb3DQEJBTEPFw0yMDA5MzAxNzAwNDZaMC8GCSqGSIb3DQEJBDEiBCC6j3WAc5BG hQKBmBtFri5+cHBYNxVs/YITkFtuxHClfDCBkQYJKwYBBAGCNxAEMYGDMIGAMGwxCzAJBgNVBAYT AlVTMRYwFAYDVQQIEw1NYXNzYWNodXNldHRzMS4wLAYDVQQKEyVNYXNzYWNodXNldHRzIEluc3Rp dHV0ZSBvZiBUZWNobm9sb2d5MRUwEwYDVQQLEwxDbGllbnQgQ0EgdjECEBqqXf02w7WotWORLaGX nXswgZMGCyqGSIb3DQEJEAILMYGDoIGAMGwxCzAJBgNVBAYTAlVTMRYwFAYDVQQIEw1NYXNzYWNo dXNldHRzMS4wLAYDVQQKEyVNYXNzYWNodXNldHRzIEluc3RpdHV0ZSBvZiBUZWNobm9sb2d5MRUw EwYDVQQLEwxDbGllbnQgQ0EgdjECEBqqXf02w7WotWORLaGXnXswDQYJKoZIhvcNAQEBBQAEggEA FlJz+hN3dfv+Vn/iqGDrIEyLvqyiRfXmJKcNk6ZlBgors/U0OZOHWOfpRWuBz3qfL2Vvh4xr8hWO RAYWlVCN9J/Wf/+yCH8d7ePX9guL6srAG598oPdK5aZlonO/MFICRqdX7+dh5Qo7aeJI3kq2z6a7 TZqk4A9zyJc4DsS/esNXR1goq6L8dcvabOdTaotYHStfe4UmVnMM3oF3M0gwJPO8hVdp1pnvDmfb Q13M6lsoDk1ICU51r+OUolB1dnVrk4Z1LPyanfpbCiZAisi7n0QeID/YcbviTp01JIGI+omGH09k r0/wFt/QxXcxiy/PfycLYnbYWSD6CSFZJJg/3gAAAAAAAA== --Apple-Mail=_93E51FD8-8E81-4D7A-AABF-DE46F386301A--