Re: toml-ts-mode: first draft

[Rudi Schlatte]

> On 13 Dec 2022, at 14:20, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Rudolf Schlatte <rudi@constantly.at>
>> Date: Tue, 13 Dec 2022 11:45:42 +0100
>> 
>> Yuan Fu <casouri@gmail.com> writes:
>> 
>>> 
>>> +  (unless (treesit-ready-p 'toml)
>>> +    (error "Tree-sitter for TOML isn't avilable”))
>>> 
>>> Treesit-ready-p already raises a warning when something goes wrong. So
>>> you want to either pass the QUIET argument or let it do the barking
>>> ;-)
>> 
>> I'd expect predicates (functions ending -p) to return T or NIL only and
>> not have side effects.
> 
> Did you read the doc string of this function?  I think it explains why
> this predicate can sometimes emit a warning and sometimes not.  It has
> more than one modus operandi.


[Attention conservation notice: this is only nitpicking about a function name; 
please do feel free to not answer this message]

The current docstring (as in the end of this mail) tells me that this predicate 
takes a second argument and has various side effects, and I can see how all 
these behaviors are useful.  But it seems the authors of a number of tree 
sitter-using modes did something like

(unless (treesit-ready-p ‘my-language)
  (warn “Didn’t find tree-sitter”))

which tells me that the authors expected treesit-ready-p to behave like other 
predicate functions, i.e., return NIL or T without side effects.  I theorize 
that this will be a recurring issue, and that using a function name not ending 
in `-p’ (e.g., (treesit-ensure-ready ‘my-language ‘message)) would remove this 
millimeter-high barrier.  But again: nitpicking, please ignore freely :)

Rudi



"Check whether tree-sitter is ready to be used for MODE and LANGUAGE.

LANGUAGE is the language symbol to check for availability.
It can also be a list of language symbols.

If tree-sitter is not ready, emit a warning and return nil.  If
the user has chosen to activate tree-sitter for LANGUAGE and
tree-sitter is ready, return non-nil.  If QUIET is t, don't emit
a warning in either case; if quiet is `message', display a message
instead of emitting a warning.”