Re: [SPAM UNSURE] Tree-sitter api

[Stephen Leake]

Yuan Fu <casouri@gmail.com> writes:

> Thank you very much for spending time on this :-)

And thank you for the same; always helpful to have different points of view.

>> The indent of every new-line must be specified; low level productions
>> can contain new-lines.
>
> Ah, I see, what I did is to find the “largest” node that starts at
> BOL, and try to match that. IIUC, wisi starts from the “smallest”
> entity, and goes up (by getting its parent repeatedly) until there is
> a non-nil indent rule for it?

That's almost right. The indent rule for each production is applied
while walking the entire syntax tree in depth-first order.

>> To be fair, we'd have to look at the other types of rules, to see if
>> this pattern holds up.
>
> I tried and all rules can be translated into wisi’s style. 

Ok.

> However, it ends up as verbose as the previous one. My idea is to
> write out match patterns (similar to that in wisi) and give names to
> the interesting ones (so we use names as opposed to position). Then,
> if any matched node happens to be the node at point, use that node’s
> corresponding indent rule to indent. And in the indent rule, we can
> refer to other matched nodes. For example, in the indent rule of
> list_rest, the anchor is list_first.
>
> Maybe there are better ways to implement this, but at its current
> stage I don’t think this is better than tree-sitter-simple-indent.

Ok.

> I think part of the reason why wisi’s indent rule can be succinct is
> that it is written along the grammar definition. It is hard to make
> tree-sitter’s indent rule as succinct while being easy to understand.

Right.

> IIUC, this tree-traversal method that you mentioned is like going
> bottom-up, and (in tree-sitter terms) match on each level, and
> accumulate indent delta for each matched indent rule, is that right?

Yes.

> Does wisi go all the way up to top-level?

Yes; the top-level rule says the indent of every line defaults to 0;
that covers any remaining 'nil' values.

I have not tried to make this part of ada-mode incremental yet (ie, only
visit changed nodes). I'm not sure that's possible.

-- 
-- Stephe