GNU/Emacs go-mode VS lsp-mode

It seems that most Go utilities have been submerged into gopls, the LSP server. So a lot of older websites that suggest how to configure go-mode might be outdated, because of the cultural shift away from the unix-ish little, collaborative utilities approach. This means you will need a LSP client -- the Go project has some documentation on that. I'd strongly recommend Eglot, if you are uncertain what to use(0). This page explains how to install gopls with your Go toolchain.

I haven't used Dash, so I don't know the specifics of what it works, but if it works like running pydoc or godoc or whatever Java has inside your text editor, here is a plugin for pydoc inside emacs and here's another for godoc (as part of a larger mode for go). I just tested godoc and it seems to work fine, if a little too basic.

This question makes very little sense to be honest. Try using spacemacs. It has a go language server runner. Otherwise try this https://github.com/dominikh/go-mode.el

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?