Re: handling many matches

[Dmitry Gutov <dgutov@yandex.ru>]

On 02.05.2020 16:52, Eli Zaretskii wrote:

> If by "look" you mean to the user, then I envision a list of
> completion candidates that somehow "knows" what I'm after, and places
> those likely guesses near the beginning of the list.

All fuzzy completion systems do that. Generally by scoring how well each 
string resembles the input string. Whether there are gaps between the 
matched characters, and so on. Our 'flex' completion style has this 
feature as well.

>>> and only after that consider changes, like the
>>> proposed "namespacing" of APIs, that will allow users to use
>>> completion as a substitute for Help commands.
>>
>> Namespacing of APIs is a step that should help the users with the
>> current default completion strategy.
> 
> Like I said, I think the hopes it will deliver a significant enough
> improvement are overrated.  It will certainly bloat the lists of
> candidates by factors, which is why I think it isn't a very good idea
> as long as we don't have some smart scoring of candidates.

The amount of "bloat" will be strictly limited by the number of aliases 
we add. I think there's a general agreement that we shouldn't go overboard.

>>> It is IMO a bad idea to
>>> flood the completion lists with many dozens of candidates and force
>>> users to wade through them.  I certainly wouldn't call that "progress"
>>> for Emacs.
>>
>> Is that what fido-mode does? People seem to like it.
> 
> I don't have a good idea of what fido-mode does, but the rather foggy
> idea I do have says it just applies fuzzy search criteria, attempting
> to find non-literal matches.  If this is so, then I don't think fido
> cuts it.

You can try it. It uses 'flex', and thus it sorts the matches based on 
scores.

> We need scoring that "learns" from what I do/did recently,
> and from my habits.  Otherwise the list of candidates will remain
> hopelessly long, with no promise of having what I'm really looking for
> anywhere near the beginning.

There are systems like that, including in third-party Emacs packages. 
Personally, I'm not fond of the idea (the unpredictability, first of 
all), and I'd rather we polish the current scoring algo first.

But it's good to have it customizable.

> Compare with the Internet search: it almost always brings me hundreds
> of hits, but I normally find what I was after among the first dozen.
> Even more spectacularly, when I type a search phrase into the search
> box, it guesses what my search phrase will be, and the guesses are
> almost always very accurate, so much so that if I don't see a long
> enough list of reasonable candidates, I usually go looking for some
> typo in what I typed (and almost always find it).  Some of the
> candidates are based on my previous search phrases, and the ones I
> typed are always ready to be reused, with a special indication to let
> me know I recently used them.

Right. There's some benefit in that. But also note that Internet 
searches can't really use fuzzy matching, at all. I'd venture to say 
that it will be difficult to combine fuzzy searches and historical 
scoring, too.