Re: Reliable after-change-functions (via: Using incremental parsing in Emacs)

[Stefan Monnier]

> I think we should try to avoid both copying and encoding the text we
> send to the parser.  Both operations are expensive and require memory
> allocation.

I think both operations are cheap enough relatively to the actual
parsing that it is not indispensable to avoid them: maybe it will be
worth the effort, but maybe not.

In any case, it's a minor implementation detail that can easily be
changed in the future without impacting the rest of the code.

So, I think it falls squarely in the realm of premature optimization.

>> According to https://github.com/tree-sitter/tree-sitter/issues/222 the
>> parse tree takes around 10 times the size of the source text.
> Yes, that's another reason why it might make sense to "forget" trees
> of buffers that were not displayed for a long time.

Agreed, tho I wouldn't word it that way: parse trees are not needed for
redisplay and can be used for things that don't relate to redisplay
(e.g. navigation, indentation, ...).

> But this is an optimization that can be added later without any
> significant changes in the design.

Agreed as well.


        Stefan