Adding comparison with Isearch MB to README

[okamsn]

isearch-mb is a new package that allows one to use Isearch in the minibuffer, similar to how CtrlF works. Maybe it is worth mentioning it in the comparisons section of the README.

• Since it is Isearch, it does not have some of the fancier CtrlF features like showing the count next to the match.
• My experience has been that for larger files (~200 MB), using this package can be much faster than using CtrlF. I think this difference is due to Isearch's lazy highlighting, but I haven't looked into it deeply.

[raxod502]

Makes sense, thanks for the pointer. Yes, indeed, CTRLF is slow for large files. That's because it's actually doing an eager search of the entire buffer every single time you move between candidates or type a character. The reason for this is because it makes the implementation much simpler. It's similar to what packages like Swiper do. Isearch, on the other hand, is basically exposing the search-forward primitive in an interactive fashion, and it has somewhat different semantics as a result.

Now I originally assumed doing a full buffer search would be a non-starter, and had ideas for how to make it asynchronous or otherwise better-optimized (e.g. searching some amount of the buffer at most and then returning control to the editor loop before moving on to the next batch). However, just doing the eager search turned out to be surprisingly fast, so I never got around to fixing this problem.