Overview

This repo includes a simple way to install some language servers that might work with YouCompleteMe (strictly ycmd).

This repo comes with no warranty, and these engines are not officially supported by YCM, though they should work for the most part.

• Overview
• Languages Tested
• Quick start
• Configuration
• Purescript
• Scala
• Haskell
• Fortran
• Ruby
• D
• Godot
• Kotlin
• Julia
• Lua
• Known Issues

Languages Tested

Working:

• Angular
• Bash
• D
• Dart
• Dockerfile
• Godot (gdscript)
• Groovy
• Kotlin
• PHP
• Ruby
• Vim (vimscript)
• Vue

Broken or partially working:

• JSON
• YAML
• Lua

See also:

• C-family with ccls

Quick start

Assuming you installed this repo in /path/to/this/directory:

• Decide which languages you want. Each language is a directory in this repo.
• Run python3 ./install.py --enable-LANG1 --enable-LANG2 .... Replace LANG1/LANG2 etc. with the language dirs. e.g. ./install.py --enable-dart --enable-bash. You can also use --all and --disable-LANG.
• Add the line to your vimrc that it tells you to, this will be similar to:

source /path/to/this/directory/vimrc.generated

• Optionally: edit vimrc.generated to customise g:ycm_language_server

• NOTE: YCM will regard the path of .ycm_extra_conf.py as root path of project folder. So please make sure you put your .ycm_extra_conf.py at right place (root of current project)

Configuration

The g:ycm_language_server option is used to tell YCM (strictly, ycmd) to use its 'generic' language server completer. It's a list of dictionaries with the following keys:

• 'name' (string): Name of the language server
• 'filetypes' (list): List of Vim filetypes to use this language server for
• 'cmdline' (list): List of words forming a command line to execute. Note: must be a list, even if it has only one element (such as [ 'executable' ]. If not supplied, no server is started and a port must be supplied.
• 'port' (number): A TCP port on localhost to connect to if stdio is not possible.
• 'project_root_files' (list, optional): List of filename to search for when trying to determine the 'root' of the project. THis is useful for languages or language servers which don't automatically detect the 'workspace' root.

For full documentation, please see the YouCompleteMe docs.

Purescript

Ycmd currently doesn't support showMessageRequest, so users need to manually build their projects on the command line before starting the server. To do this execute pulp build in the project root.

Scala

Ycmd currently doesn't support showMessageRequest, so users need to "import build" manually. Unlike purescript, for scala, this can be done in the editor by executing :YcmCompleter ExecuteCommand build-import. For this operation to succeed sbt and bloop need to be in the $PATH. metals also requires java 8.

For completions to work make sure the version of metals has this bug fix.

Haskell

haskell-ide-engine is not actively being developed anymore, in favour of haskell-language-server (installation instructions).

Fortran

The server causes a spurious error:

• fortls doesn't support didChangeConfiguration.

This error can be ignored, as they don't interfere with normal work of ycmd/fortls.

Ruby

You need to be running a version of ruby that the parser understands: https://github.com/whitequark/parser#compatibility-with-ruby-mri

Recommend running in rbenv for that:

$ rbenv shell 2.3.8
$ cd ruby
$ ./install
$ vim test/test.rb

D

There is a number of external dependencies that you will want to install:

• libphobos/liblphobos - the D standard library
• dmd - the D compiler
• dscanner - at the very least responsible for diagnostics
• dcd - the D compiler daemon
• Potentially dfmt - serve-d seems to be able to format code even without it.
• dub - the D package manager

On top of that, you will want to configure the server, at least to let serve-d know about your modules. The configuration is done through ycmd's extra confs and the full list of serve-d's configuration options can be found here.

Note that the server executable on Windows is called serve-d.exe.

Godot

Godot must be running and you must go to Project -> Project Settings -> Global and set Language Server to On.

If Godot is closed or restarted, you might need to force YCM to reconnect (this isn't automatic). Use :YcmCompleter RestartServer to reconnect.

You can check the status of the connection with :YcmDebugInfo.

Recommend vim-godot for syntax, etc. (don't believe the hype about using other completion systems though, of course).

Kotlin

For whatever reason, the server expects you to have maven in your PATH and, just like serve-d, kotlin-language-server has its own configuration.

The server executable is actually a shell script and the build process produces server for Linux and server.bat for Windows.

Make sure to put a .ycm_extra_conf.py file in the root of your project, otherwise the language server may fail.

Julia

The command line for starting the server is:

let g:julia_cmdline = ['julia', '--startup-file=no', '--history-file=no', '-e', '
\       using LanguageServer;
\       using Pkg;
\       import StaticLint;
\       import SymbolServer;
\       env_path = dirname(Pkg.Types.Context().env.project_file);
\       debug = false;
\
\       server = LanguageServer.LanguageServerInstance(stdin, stdout, debug, env_path, "", Dict());
\       server.runlinter = true;
\       run(server);
\   ']

You can replace the first command line argument ('julia') with an absolute path, if julia isn't in your $PATH. With the above list in your vimrc, you can set 'cmdline' in g:ycm_language_server to just g:julia_cmdline.

Julia server does support configuration via the extra conf, but it doesn't seem to be documented anywhere.

Lua

Uses lua-language-server.

Quick testing suggests that:

• It returns snippets even though YCM explicitly opted out, meaning completions don't work unless you use Ben's Fork
• It violates a number of other items of the protocol other than that such as missing mandatory fields.
• Signature help doesn't seem to work.

However, it looks like diagnostics and GoTo work.

The command line requeired depends on your OS:

• Windows: /path/to/lua-language-server/bin/Windows/lua-language-server.exe
• Linux: /path/to/lua-language-server/bin/Linux/lua-language-server
• macOS: /path/to/lua-language-server/bin/macOS/lua-language-server

There is one command line argument. It needs to be the absolute path to /path/to/lua-language-server/main.lua.

The install.py for Lua downloads the pre-built visual studio code extension, but you can build lua-language-server yourself easily if you have ninja installed:

git clone https://github.com/sumneko/lua-language-server
cd lua-language-server
cd 3rd/luamake
ninja ninja/<your os>.ninja
cd ../../
./3rd/luamake/luamake rebuild

This will put the binaries in bin/<your os>.

PHP

Uses Serenata.

Requires some configuration to work. Here's the minimal .ycm_extra_conf.py:

import os
ROOT = os.path.dirname( os.path.abspath( __file__ ) )

def Settings( **kwargs ):
  return {
    'ls': {
      'configuration': {
        "uris": [
          f"file://{ ROOT }"
        ],
        "indexDatabaseUri": f"file://{ ROOT }/.serenata/index.sqlite",
        "phpVersion": 7.2,
        "fileExtensions": [
          "php"
        ]
      }
    }
  }

Known Issues

• yaml completer completions don't work because the server bugs always returns snippets, even though ycmd claims not to support them. Validation works though.
• json completer completions don't work because the server bugs always returns snippets, even though ycmd claims not to support them. Validation works though.
• lua - yet another completer that returns snippets even if client doesn't support them.

There is highly experimental (essentially unsupported) support for snippet completions in Ben's Fork of YCM. For example, the following makes json work with that fork:

    \   {
    \     'name': 'json',
    \     'cmdline': [ 'node', s:lsp_dir . '/json/node_modules/.bin/vscode-json-languageserver', '--stdio' ],
    \     'filetypes': [ 'json' ],
    \     'capabilities': #{ textDocument: #{ completion: #{ completionItem: #{ snippetSupport: v:true } } } },
    \   },