Company based realtime imcremental drop-down completion menu for lsp-mode, ispell, and yasnippet.

[hongyi-zhao]

On Ubuntu 20.04, I'm using auctex, eglot, texlab, and company to build a vanilla Emacs based LaTeX document preparation system.
The detailed settings are described here. The company relevant configuration is shown below:

(use-package company)
(add-hook 'after-init-hook 'global-company-mode)

And the real effect is represented in the following screenshot:

But, I want to know if it's possible to do the regexp-based search and completion result filtering displayed on the incremental drop-down menu. For example, if I typeset \?*arrow*, then all LaTeX commands including arrow will be shown up in the drop-down menu list.

Any hints for this feature will be highly appreciated.

Regards,
HY

[dgutov]

Not regexp search, but you can type C-s arrow.

[hongyi-zhao]

Really/exactly. Wonderful. Thank you for your insightful comments. See the screenshot below:

[hongyi-zhao]

Another question I would like to know is, why do some commands have ICONS and others don't, appeared in the second to last column.

[dgutov]

Which of the icons do you mean?

[dgutov]

Ah, the arrows? Those are returned by the backend.

[hongyi-zhao]

I mean, say, for the Dirac notation, there are no icons rendered in the middle column of the drop-down menu.

But for some mathematical symbols, the corresponding icons are represented at the middle column of the drop-down menu.

[dgutov]

That's up to the backend. The language server, probably (if you're using lsp or eglot).

[hongyi-zhao]

Another issue: can I have a drop-down menu for normal writing/typesetting, just as we have for command completion with company, which is triggered by a specific threshold of the minimum number of input characters, say, 3, and then incrementally narrowed down as the input sequence increases. See here for detailed discussion.

[dgutov]

Meaning completions from words-in-buffers? Or from installed dictionaries?

[hongyi-zhao]

From installed dictionaries. Only this way is of practical application value for document writing. We can't expect all intended input words are existed in the buffer, obviously.

[dgutov]

Something like this should work:

(push '(company-capf :with company-ispell) company-backends)

Or without :with, if you're fine with only using these two backends in all your buffers.

[hongyi-zhao]

I tried with it, but noting appeared.

[dgutov]

Does M-x company-ispell work?

[hongyi-zhao]

Wonderful. See below:

But once I hint RET to insert the result at the point, I must re-run M-x company-ispell again. This makes it useless for a document preparation - the efficiency will be very poor due to run M-x company-ispell over and over.

[dgutov]

What does M-x company-diag say?

[hongyi-zhao]

What does M-x company-diag say?

[dgutov]

And what does it say after you evaluate (push '(company-capf :with company-ispell) company-backends), which you said didn't help?

[hongyi-zhao]

[dgutov]

And M-x company-diag says..?

[hongyi-zhao]

[dgutov]

The first 10 lines of that buffer are not visible, and they are the most important.

[hongyi-zhao]

Sorry for my cursory.

[dgutov]

OK, so does completion work fine in this buffer?

But it doesn't offer dictionary completions in latex buffers? If so, you have a place in your config where you set up a buffer-local value of company-backends in latex buffers. When you find it, you can add that snippet to the function that's executing there.

[hongyi-zhao]

I don't understand your meaning at all. As I've said, each completion only and must be triggered by M-x company-ispell, regardless which buffer I'm in. See the screenshots below for more detailed info.

First, run M-x company-ispell RET:

Now, the completion will be triggered:

After I hit the RET to insert the appropriate candidates from the drop-down menu, the completion will be disabled for the next word typesetting, till I re-run M-x company-ispell RET again:

[hongyi-zhao]

Company-wordfreq is a company-backend for human language texts based on word frequency dictionaries. But I still fail to try it out, as described by this issue.

[dgutov]

Hmm, I though you were using Eglot, which works through company-capf.

Try (push '(company-capf company-ispell) company-backends), then. It won't matter if capf is not used.

Or (push '(company-capf company-wordfreq) company-backends).

[hongyi-zhao]

No, this can't solve the problem. I still must run M-x company-ispell RET before type each word to trigger the dropdown completion menu. See here for relevant discussion.