doomemacs/modules/tools/lsp/README.org

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#+TITLE:    :tools lsp
#+SUBTITLE: M-x vscode
#+CREATED:  March 05, 2019
#+SINCE:    21.12.0

* Description :unfold:
This module integrates [[https://langserver.org/][language servers]] into Doom Emacs. They provide features
you'd expect from IDEs, like code completion, realtime linting, language-aware
[[doom-package:][imenu]]/[[doom-package:][xref]] integration, jump-to-definition/references support, and more.

As of this writing, this is the state of LSP support in Doom Emacs:

| Module           | Major modes                                             | Default language server                                       |
|------------------+---------------------------------------------------------+---------------------------------------------------------------|
| [[doom-module:][:lang cc]]         | c-mode, c++-mode, objc-mode                             | ccls, clangd                                                  |
| [[doom-module:][:lang clojure]]    | clojure-mode                                            | clojure-lsp                                                   |
| [[doom-module:][:lang csharp]]     | csharp-mode                                             | omnisharp                                                     |
| [[doom-module:][:lang elixir]]     | elixir-mode                                             | elixir-ls                                                     |
| [[doom-module:][:lang fsharp]]     | fsharp-mode                                             | Mono, .NET core                                               |
| [[doom-module:][:lang go]]         | go-mode                                                 | go-langserver                                                 |
| [[doom-module:][:lang haskell]]    | haskell-mode                                            | haskell-language-server                                       |
| [[doom-module:][:lang java]]       | java-mode                                               | lsp-java                                                      |
| [[doom-module:][:lang javascript]] | js2-mode, rjsx-mode, typescript-mode                    | ts-ls, deno-ls                                                |
| [[doom-module:][:lang julia]]      | julia-mode                                              | LanguageServer.jl                                             |
| [[doom-module:][:lang ocaml]]      | tuareg-mode                                             | ocaml-language-server                                         |
| [[doom-module:][:lang php]]        | php-mode                                                | php-language-server                                           |
| [[doom-module:][:lang purescript]] | purescript-mode                                         | purescript-language-server                                    |
| [[doom-module:][:lang python]]     | python-mode                                             | lsp-python-ms                                                 |
| [[doom-module:][:lang ruby]]       | ruby-mode                                               | solargraph                                                    |
| [[doom-module:][:lang rust]]       | rust-mode                                               | rls                                                           |
| [[doom-module:][:lang scala]]      | scala-mode                                              | metals                                                        |
| [[doom-module:][:lang sh]]         | sh-mode                                                 | bash-language-server                                          |
| [[doom-module:][:lang swift]]      | swift-mode                                              | sourcekit                                                     |
| [[doom-module:][:lang web]]        | web-mode, css-mode, scss-mode, sass-mode, less-css-mode | vscode-css-languageserver-bin, vscode-html-languageserver-bin |
| [[doom-module:][:lang zig]]        | zig-mode                                                | zls                                                           |

** Maintainers
/This module has no dedicated maintainers./ [[doom-contrib-maintainer:][Become a maintainer?]]

** Module flags
- +eglot ::
  Use [[https://elpa.gnu.org/packages/eglot.html][Eglot]] instead of [[https://github.com/emacs-lsp/lsp-mode][LSP-mode]] to implement the LSP client in Emacs.
- +peek ::
  Use ~lsp-ui-peek~ when looking up definitions and references with
  functionality from the [[doom-module:][:tools lookup]] module.

** Packages
- [[doom-package:][lsp-mode]]
- [[doom-package:][lsp-ui]]
- [[doom-package:][lsp-ivy]] ([[doom-module:][:completion ivy]])
- [[doom-package:][helm-lsp]] ([[doom-module:][:completion helm]])
- [[doom-package:][consult-lsp]] ([[doom-module:][:completion vertico]])
- [[doom-package:][eglot]]

** Hacks
/No hacks documented for this module./

** TODO Changelog
# This section will be machine generated. Don't edit it by hand.
/This module does not have a changelog yet./

* Installation
[[id:01cffea4-3329-45e2-a892-95a384ab2338][Enable this module in your ~doom!~ block.]]

To get LSP working, you'll need to do three things:

1. Enable this module,
2. Install a language server appropriate for your targeted language(s).
3. Enable the [[doom-module:][+lsp]] flag on the [[doom-module:][:lang]] modules you want to enable LSP support for.

Different languages will need different language servers, some of which [[doom-package:][lsp-mode]]
will prompt you to auto-install, but [[doom-package:][eglot]] will not.

A table that lists available language servers and how to install them can be
found [[https://emacs-lsp.github.io/lsp-mode/page/languages/][on the lsp-mode project README]]. The documentation of the module for your
targeted language will contain brief instructions as well.

For eglot users, a list of [[https://github.com/joaotavora/eglot/blob/master/README.md#connecting-to-a-server][default servers supported is on Eglot's README]],
including instructions to register your own.

* TODO Usage
#+begin_quote
 🔨 /This module's usage documentation is incomplete./ [[doom-contrib-module:][Complete it?]]
#+end_quote

** LSP-powered project search
Without the [[doom-module:][+eglot]] flag, and when [[doom-module:][:completion ivy]], [[doom-module:][:completion helm]] or
[[doom-module:][:completion vertico]] is active, LSP is used to search a symbol indexed by the LSP
server:
| Keybind | Description                         |
|---------+-------------------------------------|
| [[kbd:][SPC c j]] | Jump to symbol in current workspace |
| [[kbd:][SPC c J]] | Jump to symbol in any workspace     |

** Differences between eglot and lsp-mode
Entering the debate about which one to use would be useless. Doom provides an
easy way to switch out lsp client implementations so you can test for yourself
which one you prefer.

Mainly, from a code point of view, lsp-mode has a lot of custom code for UI
(~lsp-ui-peek~, ~lsp-ui-sideline~, ...), while eglot is more barebones with a
closer integration with "more basic" emacs packages ([[doom-package:][eldoc]], [[doom-package:][xref]], ...).

* TODO Configuration
#+begin_quote
 🔨 /This module's configuration documentation is incomplete./ [[doom-contrib-module:][Complete it?]]
#+end_quote

** Turn off lsp-mode's intrusive features
Many users may not like how many UI elements that lsp-mode adds. They have [[https://emacs-lsp.github.io/lsp-mode/tutorials/how-to-turn-off/][some
excellent documentation]] outlining what these features are called and how to turn
them off.

* Troubleshooting
[[doom-report:][Report an issue?]]

** My language server is not found
Check the entry in the [[../../../docs/faq.org][FAQ]] about "Doom can't find my executables/doesn't inherit
the correct ~PATH~"

** LSP/Eglot is not started automatically in my buffer
Make sure that you have enabled the [[doom-module:][+lsp]] flag on the appropriate module(s) (in
your ~doom!~ block in =$DOOMDIR/init.el=):
#+begin_src diff
:lang
-python
+(python +lsp)
#+end_src

** LSP is slow
Follow [[https://emacs-lsp.github.io/lsp-mode/page/performance/#tuning][lsp-tuning-guide]] to further fine-tune LSP mode performance.

* Frequently asked questions
/This module has no FAQs yet./ [[doom-suggest-faq:][Ask one?]]

* TODO Appendix
#+begin_quote
 🔨 This module has no appendix yet. [[doom-contrib-module:][Write one?]]
#+end_quote