Re: Inline completion preview

[Eshel Yaron]

Eli Zaretskii <eliz@gnu.org> writes:

>> > Then maybe you should describe the use case in more details, because
>> > this could be a misunderstanding of sorts.  What are the use case(s)
>> > where the feature you propose would be useful?
>> 
>> The use case is this: you're editing some code, maybe it's a language
>> you're not extremely proficient with, and you want your editor (Emacs)
>> to give you suggestions for code that it would make some sense to write.
>> Completion preview does that by showing you a completion candidate you
>> can insert, and displaying it as if you've already inserted it, so you
>> know exactly what it'll look like (you get a preview).  As you are
>> typing, Emacs updates the suggestion based on your keystrokes.  If you
>> couple that with a good completion backend, you get useful suggestions
>> with a very low friction interface.
>
> If you are talking about code completion, showing a single candidate
> is rarely TRT, especially in programming languages that support
> polymorphism.

Yes, I'm talking about showing a single code completion candidate, in a
special way, that happens automatically under certain conditions, and
that is independent of how you otherwise view your list of completion
candidates (be it the *Completions* buffer or in some other popup) when
you trigger in-buffer completion.  For clarity, I'm attaching below a
screenshot showing how such completion preview in an Elisp buffer.
Sometimes, previewing just one candidate that way can be quite useful,
for example when there's only one matching completion candidate for
whatever you're typing.  In completion-preview.el there's a user option
`completion-preview-exact-match-only` that lets you require exactly this
condition for showing the completion preview.  In Company, that's the
default behavior (showing such a preview when there exactly one matching
candidate).

Screenshot 2023-10-27 at 8.05.12 PM.png
Description: PNG image