ctags VS lsp-mode

I also recommend you https://github.com/preservim/tagbar with https://ctags.io/ installed , it will map definitions (functions, enum, struct etc..) to tags and tagbar plugin allows you to open a split window with the mapped list and navigate through your file, it also enabled more advanced features for quick navigation .

grep, Ctags, Cscope, LSP

Vim has the tag feature built-in, which allows it to jump to the tags that were found by a tool like universal ctags using :h CTRL-]. See :help tags for more information on this. Fun fact: this is the approach that Vim uses when you use :help!

Requirements: You need to have a CTags implementation like universal-ctags installed on your system (on every system where you use vim).

Install https://github.com/universal-ctags/ctags

If you are heavy Vim user, you do not need anything else. For just quick browsing, simply use ctags, make sure to use universal ctags (https://ctags.io) not exuberant ctags which are no longer well maintained. Go works out of box.

Other (built-in) tools for file navigation in Vim include: :h :ls and :h :buffer to navigate in your buffer list (i.e. the files you have loaded); everything listed in [https://vimways.org/2018/death-by-a-thousand-files/](romainl's "Death by a Thousand Files" articles in vimways); using tags by installing universal-ctags to generate the tags then using any of the commands in :h tag to navigate them; setting global marks to files you use often with m[UPPERCASE LETTER] and jumping to them with `[UPPERCASE LETTER]; :h :vimgrep…

I have good news for you. Universal Ctags, an Exuberant Ctags fork and essentially its replacement, has fixed this already:

Vim has built-in functionality that works pretty similar to what you want. If you have a tags file (for example, using universal ctags), you can hit Ctrl-] (:h Ctrl-]) to jump to the declaration of any function under your cursor. Or, if you don't have a tags file, you can use gd (:h gd) to jump to a local declaration within the open file.

I also tried to the solutions suggested  and , but nothing worked. I moved the (setq lsp-keymap-...) line outside (and before) use-package. I also used :config (define-key lsp-load-map...) in my use-package block. But none of them worked.

Not sure how much this might help, but lsp-mode has lsp-yaml-select-buffer-schema and lsp-yaml-set-buffer-schema commands to pick schema from a list or set from a URI. Checking the source of them might give some hints about how the same could be implemented in eglot?

Beyond that you might as well embrace the suck and install autex with a language server: https://emacs-lsp.github.io/lsp-mode/

Smart completion these days is done primarily through LSP. eglot is fairly minimal but built-in as of 29, also available via GNU Elpa. lsp-mode is another option with more integrations and a bit more fleshed out.

lsp-mode: https://github.com/emacs-lsp/lsp-mode/issues/2080

Are you running emacs-29? It has numerous speed-ups compared to emacs-28 and older versions, many of them coded by Mattias Engdegård, e.g. commit def6fa4246. I have a fresh build of emacs-29 running on Linux and a new mac with an M1 CPU, and it's stupid fast. I don't use the native-comp feature. I rarely notice any hesitation or slowness. I don't use Elpy. I do use lsp mode.

Since you are doing code development, the first things to go for would be setting up your emacs packaging (installing use-package and melpa (use-package's documentation covers this) so you have more packages to choose from (do be careful to not just pick things willy nilly but research them a bit first)) and then setting up lsp-mode. lsp-mode lets you use LSP servers for the specific programming languages you work with in a somewhat unified fashion. You then need to install and setup the LSP servers for the languages you use, and possibly install language specific Emacs packages as support (note, Emacs has builtin functionality for many).

And first of all, I'm trying to understand, how is it connected to https://github.com/emacs-lsp/lsp-mode? I'm sure, that existed lsp implementations already parse source code. Why TreeSitter?