Subject: Re: bug#67262: python-ts-mode cannot identify triple-quoted-strings

From: Dmitry Gutov <[email-masked]>
Date: Tue, 12 Dec 2023 23:55:43 +0200

On 12/12/2023 10:32, Yuan Fu wrote:

>> syntax-ppss-flush-cache is called by edits (and by the re-parse). It 
>> seems like it will be odd to have execution the other way around 
>> and/or add some hook into it which would call the re-parse and extend 
>> the region to be invalidated.
>>
>> syntax-propertize could have another hook added, yes. Or an advice.
>>
>> But it seems better to reuse some of the existing hooks, such as 
>> syntax-propertize-extend-region-functions. It treesit.c provided a way 
>> to fetch the newly-invalidated region, the treesit-major-mode-setup 
>> could add a new function to syntax-propertize-extend-region-functions 
>> which would invoke that feature. But even now it can instantiate the 
>> parse, which would call treesit-force-reparse internally, and then 
>> collect the info from the callbacks.
> syntax-propertize-extend-region-functions looks perfect. We just need to 
> force a reparse in it and the notifier will do the rest.
>>
>> And yet another way - is to extend the region to be propertized from 
>> inside the major mode's syntax-propertize-function, invalidating some 
>> earlier entries too. The main problem with that, I think, is that 
>> every ts mode will have to repeat that trick. And that authors would 
>> have to know to do that. How to make that easier and more obvious, is 
>> a question.
>>
>> Finally, if I'm right that bug#66732 has a similar cause, then a 
>> shared solution that can be reused by syntax and font-lock (or 
>> preferably just fix both in the same place) would be ideal.
>>
>>> I'm not quite sure about how do we cause this re-parse. The 
>>> straightforward approach would be calling treesit-force-reparse[1] in 
>>> syntax-propertize/syntax-ppss-flush-cache. But ideally I'd like to 
>>> keep tree-sitter transparent for syntax.el. Maybe we can add a hook 
>>> in syntax-propertize/syntax-ppss-flush-cache.
>>>
>>> [1] This function doesn't exist yet, but it's easy to define in lisp.
>>
>> treesit-parser-root-node calls it anyway and does little else, so we 
>> could get by with just using it.
>>
> Yep.

For the casual observer: I posted a solution using the above method in 
comments to bug#66732 yesterday.