[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Recent updates to tree-sitter branch
From: |
Ihor Radchenko |
Subject: |
Re: Recent updates to tree-sitter branch |
Date: |
Mon, 26 Sep 2022 17:43:34 +0800 |
Yuan Fu <casouri@gmail.com> writes:
>> treesit-font-lock-rules rules take a form of
>> (MATCHER FACENAME) or (MATCHER FUNCTION)
>>
>> where MATCHER can only be a query.
>>
>> Is there any reason why MATCHER in treesit-font-lock-rules cannot be a
>> function with access to the fontified node?
>
> Hmm, I’m not sure what do you mean. The whole thing passed to
> treesit-font-lock-rules is a single query, and we can’t really change the
> query syntax, that’s defined by tree-sitter. Basically in a query you have
> patterns paired with capture names, if the pattern matches to a node, that
> node is returned with corresponding capture name tagged on it. For font-lock,
> we just use face names as capture names, and when a query returns captured
> nodes, fontify the node with its capture name, aka a face (or a function).
What I am asking is an extra dynamic condition in addition to the query.
For example:
1. Only apply FACENAME for nodes matching QUERY, but only when Elisp
variable is non-nil
2. Only apply FACENAME for nodes matching QUERY, which are in the second
half of the buffer
3. Only apply FACENAME for notes matching QUERY, which also have a field
matching a dynamically assigned regexp.
Essentially any condition that is not covered by the QUERY, but can be
checked in Elisp given that node object is passed to the test function.
>> Further, can OVERRIDE FLAG of the MATCH-HIGHLIGHT as in
>> font-lock-keywords be supported?
>>
>> "If OVERRIDE is t, existing fontification can be overwritten. If
>> keep, only parts not already fontified are highlighted. If prepend or
>> append, existing fontification is merged with the new, in which the new
>> or existing fontification, respectively, takes precedence.”
>
> I can do that, but would it be really useful? Unlike regex font-lock which is
> used for so many different things, tree-sitter font-lock is, IMO, only used
> to apply a base layer of language-specific highlight. How would one use the
> override feature in this scenario?
For example, consider a function definition with docstring field.
Imagine that you want the function definition to have gray background,
but the docstring to have yellow background. OVERRIDE t is how this is
usually implemented in font-lock-keywords.
--
Ihor Radchenko,
Org mode contributor,
Learn more about Org mode at https://orgmode.org/.
Support Org development at https://liberapay.com/org-mode,
or support my work at https://liberapay.com/yantar92
Re: Recent updates to tree-sitter branch, Aurélien Aptel, 2022/09/29