elm-language-server
This is the language server implementation for the Elm programming language.
Table of Contents
- Installation
- Requirements
- Features
- Server Settings
- Editor Support
- Awesome libraries this is based on
- Contributing
Installation
Note for VSCode users: The plugin contains the language-server. No installation necessary.
The server can be installed via npm
(or from source).
npm install -g @elm-tooling/elm-language-server
Then, you should be able to run the language server with the following command:
elm-language-server
Follow the instructions below to integrate the language server into your editor.
Alternative: Compile and install from source
First, clone this repo and compile it. npm link
will add elm-language-server
to the PATH
.
git clone git@github.com:elm-tooling/elm-language-server.git
cd elm-language-server
npm install
npm run compile
npm link
Nix
Alternative: Install withelm-languager-server
and its dependencies are available in nixpkgs
.
nix-env -i -A nixpkgs.elmPackages.elm-language-server
Requirements
You will need to install elm
and elm-test
to get all diagnostics and elm-format
for formatting. Alternatively you can also just install these to your local npm package.json
.
npm install -g elm elm-test elm-format
Or use local versions from your node_modules
directory, if you want to do that you need to set the paths, via the settings (e.g. set elmPath
to ./node_modules/.bin/elm
).
Features
Supports Elm 0.19 and up
Feature | Description |
---|---|
diagnostics | Provided via elm , elm-test and elm-analyse |
formatting | Provided via elm-format and post-processed to only return a diff of changes. This way it should not be as intrusive as running elm-format normal |
codeLenses | Currently only shows if a type alias, custom type or function is exposed from that module |
completions | Show completions for the current file and snippets |
definitions | Enables you to jump to the definition of a type alias, module, custom type or function |
documentSymbols | Identifies all symbols in a document. |
folding | Let's you fold the code on certain Elm constructs |
hover | Shows type annotations and documentation for a type alias, module, custom type or function |
references | Lists all references to a type alias, module, custom type or function |
rename | Enables you to rename a type alias, module, custom type or function |
workspaceSymbols | Identifies all symbols in the current workspace |
selectionRange | Enables navigation by selectionRange (extend selection for e.g.) |
Server Settings
This server contributes the following settings:
elmLS.trace.server
: Enable/disable trace logging of client and server communicationelmLS.elmPath
: The path to yourelm
executable. Should be empty by default, in that case it will assume the name and try to first get it from a local npm installation or a global one. If you set it manually it will not try to load from the npm folder.elmLS.elmFormatPath
: The path to yourelm-format
executable. Should be empty by default, in that case it will assume the name and try to first get it from a local npm installation or a global one. If you set it manually it will not try to load from the npm folder.elmLS.elmTestPath
: The path to yourelm-test
executable. Should be empty by default, in that case it will assume the name and try to first get it from a local npm installation or a global one. If you set it manually it will not try to load from the npm folder.elmLS.elmAnalyseTrigger
:elm-analyse
executed on'change'
,'save'
or'never'
(default:'change'
)
Settings may need a restart to be applied.
Elm-Analyse Configuration
elm-analyse
is used for static code analysis. All checks are enabled by default. An (optional) elm-analyse.json
configuration file will be respected, if added to your project.
See its documentation for details regarding configuration
and checks
.
Editor Support
Editor | Diagnostics | Formatting | Code Lenses | Completions | Definitions | Document Symbols | Folding | Hover | References | Rename | Workspace Symbols |
---|---|---|---|---|---|---|---|---|---|---|---|
VSCode | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
VIM CoC | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
VIM LanguageClient | ✔️ | ✔️ | ❔ | ✔️ | ❔ | ❔ | ❔ | ❔ | ❔ | ❔ | ❔ |
VIM ALE | ✔️ | ❌ | ❌ | ❔ | ✔️ | ❌ | ❌ | ✔️ | ✔️ | ❌ | ✔️ |
Kakoune | ✔️ | ✔️ | ❔ | ✔️ | ✔️ | ✔️ | ❔ | ✔️ | ✔️ | ✔️ | ❔ |
Emacs | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ❔ | ✔️ | ✔️ | ✔️ | ✔️ |
Sublime | ✔️ | ✔️ | ❌ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ |
VSCode
Just install the elm-tooling/elm-language-client-vscode
plugin from the VSCode MarketPlace
Vim
There are general setup instructions and FAQ for Vim.
It's recommended to install syntax highlighting, which also adds the required detection of elm as filetype
. An example vim configuration can be found in elm-vim/vim-config-example.
coc.nvim
To enable support with coc.nvim, run :CocConfig
and add the language server config below.
If needed, you can set the paths to elm
, elm-test
and elm-format
with the elmPath
, elmTestPath
and elmFormatPath
variables.
{
"languageserver": {
"elmLS": {
"command": "elm-language-server",
"filetypes": ["elm"],
"rootPatterns": ["elm.json"],
"initializationOptions": {
"elmAnalyseTrigger": "change"
}
}
},
// If you use neovim you can enable codelenses with this
"codeLens.enable": true
}
Much of this is covered in the Example vim configuration section in Coc's readme.
Feature | How to use it |
---|---|
Diagnostics | :CocList diagnostics Configure refresh with "diagnostic.refreshAfterSave": false |
Formatting | :call CocAction('format') |
CodeLenses | Requires Neovim. Add "coc.preferences.codeLens.enable": true to your coc-settings.json through :CocConfig |
Completions | On by default, see Completion with sources for customizations |
Definitions | Provided as <Plug> mapping so that you can set it yourself, e.g. nmap <silent> gd <Plug>(coc-definition) nmap <silent> gy <Plug>(coc-type-definition) |
DocumentSymbols | :CocList outline |
Folding | You must set foldmethod=manual in your vimrc , one set Coc will handle folding with the usual commands, zc , zo , etc |
Hover | :call CocAction('doHover') |
References | Provided as a <Plug> mapping, e.g. nmap <silent> gr <Plug>(coc-references) |
Rename | Provided as a <Plug> mapping, e.g. nmap <leader>rn <Plug>(coc-rename) |
Workspace Symbols | :CocList symbols |
ALE
ALE contains the elm_ls
linter.
let g:ale_linters = { 'elm': ['elm_ls'] }
If needed, you can set the paths to elm
, elm-test
and elm-format
. The configuration can be found here
let g:ale_elm_ls_use_global = 1
let g:ale_elm_ls_executable = "/path/to/elm-language-server"
let g:ale_elm_ls_elm_analyse_trigger = 'change'
let g:ale_elm_ls_elm_path = "/path/to/elm"
let g:ale_elm_ls_elm_format_path = "/path/to/elm-format"
let g:ale_elm_ls_elm_test_path = "/path/to/elm-test"
Feature | How to use it |
---|---|
Diagnostics | :ALENext /:ALEPrevious Configure refresh with let g:ale_lint_on_text_changed = 0 let g:ale_lint_on_insert_leave = 1 let g:ale_lint_on_save = 1 |
Formatting | ALE doesn't currently support this through the language server integration, but elm-format is a supported ALE Fixer |
CodeLenses | Not currently supported |
Completions | On by default, see :h ale-completion for more info |
Definitions | :ALEGoToDefinition , :ALEGoToTypeDefinition , see :h ale-go-to-definition and :h ale-go-to-type-definition |
DocumentSymbols | Only workspace symbols are currently supported |
Folding | Not currently supported |
Hover | :ALEHover |
References | :ALEFindReferences |
Rename | Not currently supported |
Workspace Symbols | :ALESymbolSearch <query> |
LanguageClient
To use this language server with LanguageClient add the following configuration to you neovim/vim.
let g:LanguageClient_serverCommands = {
\ 'elm': ['elm-language-server'],
\ }
let g:LanguageClient_rootMarkers = {
\ 'elm': ['elm.json'],
\ }
Kakoune
kak-lsp
First install kak-lsp, and enable it in the kakrc. One way would be to add these lines to your .config/kak/kakrc file:
eval %sh{kak-lsp --kakoune -s $kak_session}
lsp-enable
Then, assuming installation of elm-language-server
, elm-format
, and elm-test
, add this section to your .config/kak-lsp/kak-lsp.toml
file:
[language.elm]
filetypes = ["elm"]
roots = ["elm.json"]
command = "elm-language-server"
[language.elm.initialization_options]
elmAnalyseTrigger = "change"
Emacs
The language client is included in lsp-mode, specifically here. See specifically this section for a minimal use-package configuration for lsp-mode.
Emacs Doom
- Uncomment
lsp
andelm
in your configuration file.doom.d/init.el
and add the+lsp
feature flag to the elm layer:
lsp
(elm +lsp)
- Optional configuration for lsp-mode and lsp-ui-mode. Add this to your
.doom.d/config.el
:
(after! lsp
(setq lsp-enable-symbol-highlighting nil)
)
(after! lsp-ui
(setq lsp-ui-doc-max-width 100)
(setq lsp-ui-doc-max-height 30)
(setq company-lsp-cache-candidates nil)
)
- Run
~/.emacs.d/bin/doom sync
Feature | How to use it |
---|---|
Diagnostics | On by default |
Formatting | On save |
CodeLenses | lsp-lens-mode , lsp-show-lens |
Completions | On by default |
Definitions | lsp-find-definition , lsp-ui-peek-find-definitions |
DocumentSymbols | lsp-ui-imenu |
Folding | +fold/open , +fold/close |
Hover | lsp-ui-sideline-mode , lsp-ui-doc-mode , lsp-ui-show-doc |
References | lsp-ui-peek-find-references , lsp-find-references |
Rename | lsp-rename |
SelectionRange | lsp-extend-selection |
Sublime
- Install Elm Syntax Highlighting, LSP and LSP-elm from Package Control.
- Restart Sublime.
You should now be able to use the integrations from Sublime. You might want to read about the features offered
Awesome libraries this is based on
Contributing
Please do :) As the best thing about a language server is that multiple clients will improve that way.