From: "Óscar Fuentes" <oscarfv@telefonica.net>
To: Yuan Fu <casouri@gmail.com>
Cc: Eli Zaretskii <eliz@gnu.org>, 71086@debbugs.gnu.org
Subject: bug#71086: 30.0.50; Setting treesit-indent-function is not effective is treesit-simple-indent-rules is nil
Date: Wed, 22 May 2024 16:15:13 +0200 [thread overview]
Message-ID: <87cypec4r2.fsf@telefonica.net> (raw)
In-Reply-To: <EF75EFCE-99BA-4951-AFB2-2334124D20DE@gmail.com> (Yuan Fu's message of "Tue, 21 May 2024 23:23:30 -0700")
Yuan Fu <casouri@gmail.com> writes:
> There are actually another level of customization between setting
> treesit-simple-indent-rules and setting indent-line-function, which is
> setting treesit-indent-function. IIUC Óscar is trying to do that but
> found out treesit-major-mode-setup doesn’t automatically setup
> indent-line-functions when treesit-indent-function is set.
More specifically, I found that treesit-major-mode-setup doesn't setup
indentation when treesit-simple-indent-rules is *not* set, even when
treesit-indent-function has been set.
> I’ve now fixed that.
Indeed, thank you.
> (Though I didn’t expect someone to use this variable.)
Why not? It is documented and the natural alternative when
treesit-simple-indent-rules is not fit for the job, isn't it?
> And to Óscar, I’m curious and interested to know what indentation
> function you came up with; if it’s useful maybe we can add it to
> Emacs?
I started with treesit-simple-indent-rules until I stumbled on something
that it is not easily workable with the existing functions. My language
has a Lisp syntax, and the problem was with indenting comments (and with
how the presence of comments affected the indentation of other things).
For instance, the typical indentation of
(if p
foo
bar)
That's simple enough to achieve with treesit-simple-indent-rules, but if
we insert a comment:
(if p
;; blah
(foo)
(bar))
things suddenly turn hairy.
Likewise, starting with this:
(progn (foo)
(bar))
... after inserting a comment, this is the desired indentation:
(progn ;; blah
(foo)
(bar))
... not this:
(progn ;; blah
(foo)
(bar))
Maybe a variant of `match' and `nth-sibling' that take an argument of
node types to skip would be enough to cover this case? That was
basically what I did.
Anyways, going the treesit-indent-function route was easy enough, and it
is more powerful, flexible and future-proof. I don't think that
treesit-simple-indent-rules would yield a significantly shorter and
mantainable implementation.
> I also updated the manual.
Thanks!
BTW, the treesit-based implementation of the major mode for this simple
language is a tiny fraction of its traditional counterpart. And
providing a great basis for adding more features :-)
next prev parent reply other threads:[~2024-05-22 14:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-21 1:32 bug#71086: 30.0.50; Setting treesit-indent-function is not effective is treesit-simple-indent-rules is nil Óscar Fuentes
2024-05-21 11:43 ` Eli Zaretskii
2024-05-22 6:23 ` Yuan Fu
2024-05-22 14:15 ` Óscar Fuentes [this message]
2024-06-02 16:55 ` Óscar Fuentes
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