From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Theodor Thornhill Newsgroups: gmane.emacs.devel Subject: Re: Plug treesit.el into other emacs constructs Date: Wed, 14 Dec 2022 22:15:34 +0100 Message-ID: <87359h1ybt.fsf@thornhill.no> References: <87wn6whete.fsf@thornhill.no> <87r0x3gnv5.fsf@thornhill.no> <04BB786A-3ED1-4918-8583-17AA01A1E453@gmail.com> <4E3940CA-67A6-45B7-8785-4E60FDECCDFB@gmail.com> <4315EFC6-7AA8-4A48-845C-9CA8B88034D9@thornhill.no> <87bko521n0.fsf@thornhill.no> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="14351"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Yuan Fu , emacs-devel@gnu.org, eliz@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Dec 14 22:16:06 2022 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 1p5Z6j-0003Sq-B5 for ged-emacs-devel@m.gmane-mx.org; Wed, 14 Dec 2022 22:16:05 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p5Z6O-0006qt-5I; Wed, 14 Dec 2022 16:15:44 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p5Z6L-0006qR-FV for emacs-devel@gnu.org; Wed, 14 Dec 2022 16:15:42 -0500 Original-Received: from out2.migadu.com ([188.165.223.204]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p5Z6I-0005xH-M1; Wed, 14 Dec 2022 16:15:40 -0500 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. 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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-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:301414 Archived-At: Stefan Monnier writes: >>>>>In this case, yes. But in other cases it will move at different levels >>>>>of the tree. E.g.: >>>>> >>>>> int x = f (b + 4, c * 7 - z * 2, d, e); >>>>> >>>>>It will sometimes move over the whole instruction, and other times over >>>>>just a single variable or over a whole argument or over just a "factor". >>>>>This depends on where point is when `forward/backward-sexp` is called. >>>> >>>> Yeah. I think this example shows what I find unintuitive. If point is right >>>> before the first comma, and we transpose-sexps, it could end up swapping >>>> 4 for c * 7 - z * 2, which would rarely make sense in this context. >>> >>> If so, that would be a bug in `transpose-sexp`, agreed. >>> I'm talking here about `forward/backward-sexp`. >>> The two are linked, but we shouldn't use one to justify a bug in the other. >> >> Sure, but I think they necessarily needs to be viewed as a whole. If we >> drop tree-sitter or SMIE (which I actually know pretty well) for one >> moment, the cc-mode based java-mode would exhibit the exact behavior I >> described. > > Really? When I try it out in CC-mode's java-mode, I get from > > int x = f (b + 4|, c * 7 - z * 2, d, e); > to > int x = f (b + c, 4| * 7 - z * 2, d, e); > > which is not completely non-sensical, but is somewhere between a bug and > a misfeature. Yeah, I misspoke, sorry. I get the same, and obviously agree. I believe I wanted to say something like "I get the same behavior with transpose-sexps as with transpose-word", or something like that. > >> If it's a bug in tranpsose-sexps it is definitely an issue >> with forward/backward-sexp, because in every situation the positions to >> be swapped is just "backward-sexp - forward-sexp - forward-sexp - >> backward-sexp", right? > > The way I see it, the problem with sexp movement and infix syntax is > that a given buffer position maps to several positions at different > levels in the AST (contrary to Lisp style syntax where there is no such > ambiguity). > > So for every command, we need to decide/guess at which level of the AST > the user wants to operate. For `transpose-sexp` we have more > information than for `forward/backward-sexp` because some of those > positions are "non-sensical" in the sense that they would end up swapping > subtrees that live at different levels or that do not share their > immediate parent. > > For this reason, what we should do with `transpose-sexp` is not necessarily > exactly the same as what we should do with `backward/forward-sexp`. > Yeah, I agree. I could create a treesit-transpose-sexps that doesn't use forward-sexp and uses the 'special (which probably should be documented) argument, similarly to how it's implemented now. >> And the thing in the middle, usually a comma, >> operators or other is the space between that doesn't move. I also >> observe this fixme inside of transpose-words: >> >> ;; FIXME: `foo a!nd bar' should transpose into `bar and foo'. >> >> I read this more like it's how transpose-sexps should behave on text. > > IIRC I wrote this when I was working on the SMIE `transpose-sexp` code :-) > >> Wouldn't it make sense to make transpose-sexps actually do what that >> fixme asks? > > I obviously agree, since I wrote that fixme. > Great. It seems there has been almost no development, nor documentation done in this area for a long time. Should I try to improve on this part of the code while I'm at it? >> And why is the >> >> (cons (progn (funcall mover x) (point)) >> (progn (funcall mover (- x)) (point))) >> >> in this form, and not some pseudo-code like: >> (cons '(backward-thing-from-start-point forward-thing-point) >> '(forward-thing-from-start-point backward-thing-point)) > > Sorry, haven't looked at the code in a while. > Not sure what you're getting at here. I suspect that in the case of > tree-sitter you'd ideally want to implement `transpose-sexp` directly > rather than via something like `forward/backward-sexp`: > - Go from point to a node in the tree. > - Find the node whose children we want to swap. > - Find the bounds of those two children. > - Do the actual textual swap. > Yeah, that's what I'm thinking too. I'm just thinking we should be clear on what a word/sexp/sentence/paragraph/defun etc is in non-lisp and non-human languages. >> Now I'm having issues where movement over sexps ends up not in the >> same place. > > Same place as? > IIRC there's no guarantee that the movement sequence used for transpose-sexp moves over the same blocks of code, so in non-lisp languages there's no real semantic to go from. I'll find an example. Theo