bug#44418: 28.0.50; Spliced variable not matched as symbol in isearch

[Yuan Fu]

> On Jun 24, 2023, at 3:12 AM, Mattias Engdegård <mattias.engdegard@gmail.com> 
> wrote:
> 
> 24 juni 2023 kl. 00.39 skrev Yuan Fu <casouri@gmail.com>:
> 
>> I want to point out that a) this will add complexity and make the syntax
>> harder to read and learn (however minuscule the impact might be); b) is
>> not enough by itself to make isearch symbol work with capture names:
>> whoever write the code must _use_ this syntax; and c) I don’t think
>> isearch symbol itself is popular/important enough to justify the change.
> 
> Well, you are the treesit maintainer and get to decide, but perhaps I could 
> try to sway your opinion. First note that the change is very small with no 
> increase in complexity -- most treesit users would never bother to learn that 
> there is an alternative @SYMBOL notation in addition to the standard (@ 
> SYMBOL).
> 
> Furthermore, the @SYMBOL notation is quite un-Lisp-like and alien to Lisp 
> programmers who definitely tend to make use of symbol search, which is why 
> this bug (about the ,@ prefix) was so annoying: it not only prevented us from 
> effectively finding all occurrences of a symbol, but deprived us of a common 
> way to check that the spelling of name is correct and corresponds to its 
> definition. A pity if we now introduce the same kind of bug again, unforced.
> 
> I did a quick translation of some treesit patterns in various language modes 
> from @SYMBOL to (@ SYMBOL) and the result was no less readable. Try it 
> yourself.
> 
> Your decision to expose treesit queries as Elisp S-expressions was fortunate, 
> as can be seen by the fact that no Emacs editing mode seems to use the other 
> (string) syntax, and the modes make frequent use of backquote forms to 
> interpolate Lisp values into patterns.

Sorry for taking so long, I never decided against other people for important 
things in Emacs, and I certainly don’t want to make a wrong decision and regret 
it later, so I struggled a bit and kept procrastinating 😃

I agree that it’s easy to figure out what does the detached @ syntax mean. I 
mainly just don’t like having two ways to do the same thing.

Since I don’t use search symbol myself, I can’t grasp the importance of it. You 
apparently care about it enough to go this far, and I’m willing to take your 
word for it.

You mentioned sexp queries, which reminded me that using the detached syntax 
would allow people to interpolate capture names with quasi quotes. That’s a 
plus for the detached syntax.

Ultimately I’m still on the fence for this. But if you still want to add it, 
please go ahead :-)

Yuan