Language Support

Language Support

Oni utilizes the Language Server Protocol (LSP) to provide common IDE functionality for any arbitrary programming language. This enables features like code completion, go-to definition, and method signature help.

• Included Language Servers
• Configuration
  • Auto-Closing Pairs
  • Language Servers
  • Other Settings
• Language Notes
  • Bash
  • C/C++
  • C#
  • Dart
  • Docker
  • Go
  • Haskell
  • Java
  • JavaScript and TypeScript
    • JavaScript and Flow
    • Javascript and Vue
  • Lua
  • Python
  • Reason and OCaml
  • Ruby
  • Rust

Included Language Servers

Oni comes with a few language servers bundled:

• HTML - provided by vscode-html-languageserver-bin
• CSS/LESS/SASS - provided by vscode-css-languageserver-bin
• JavaScript/TypeScript - provided by typescript's Standalone Server
• Reason / OCaml - provided by ocaml-language-server

Configuration

Language options are configurable via the configuration settings in your config.js.

In general, language options are specified in the form language.<language-identifier>.<option>, where language-identifier corresponds to the file type.

Auto-Closing Pairs

Auto-closing pairs is a feature that automatically 'closes' certain character pairs.

This has two general settings:

• autoClosingPairs.enabled - (boolean) - specifies whether auto-closing pairs are active. Default is true.
• autoClosingPairs.default - (AutoClosingPair[]) - specifies the default set of auto-closing pairs, if not overridden by a language setting.

With the default set of auto-closing pairs defined as:

    "autoClosingPairs.default": [
        { "open": "{", "close": "}" },
        { "open": "[", "close": "]" },
        { "open": "(", "close": ")" },
    ],

Auto-closing pairs can be specified per language via the language.<language-identifier>.autoClosingPairs setting, in the same format as above.

Language Servers

Language servers are configurable via the language.<language-identifier>.languageServer.<setting>, and the following settings are available:

• command - (String) (required) - The command to start the language server. This could be a javascript file or an executable. REQUIRED
• arguments (String[]) (optional) - An array of arguments to pass to the language server
• rootFiles (String[]) (optional) - A set of files that are treated as the root. When this is specified, Oni will search upward for this, and start the language server in the root folder
• configuration (any) (optional) - Additional javascript objects to send to the language server via the workspace/onConfigurationChanged event

An example configuration might be:

"language.reason.languageServer.command": "ocaml-language-server",
"language.reason.languageServer.arguments": ["--stdio"],
"language.reason.languageServer.rootFiles": [".merlin", "bsconfig.json"],
"language.reason.languageServer.configuration": {}

The only required option is the language server command, however, some language servers may require you to use the full set of parameters.

NOTE: Language servers implement different transports - stdio, ipc, socket. Today, Oni only supports stdio

To find a language server, check out langserver.org

Other Settings

Aside from language servers, there are other settings available for customizing languages in Oni:

• language.<language-identifier>.completionTriggerCharacters (string[]) - an array of characters that can trigger completion.

• NOT IMPLEMENTED YET - language.<language-identifier>.autoPairs

Language Notes

Bash

Bash language support is provided via the bash-language-server.

Example Bash configuration:

"language.bash.languageServer.command": "bash-language-server",
"language.bash.languageServer.arguments": ["start"],

C/C++

C and C++ language support is set up by default to use clangd, and expects clangd available in your path.

• Get a working clangd (both code and executables are available here)
• Make sure that clangd is available globally (for instance, by adding it to an environment variable)

For information on setting it up, please refer to the clangd documentation.

C#

C# language support is not configured by default, and requires the oni-language-csharp plugin, which provides language capabilities for both .NET and Mono.

Follow the installation instructions to get started.

Dart

Dart language support is provided via the dart_language_server.

Example Dart configuration:

"language.dart.languageServer.command": "dart_language_server",

Docker

Docker language support is provided via the dockerfile-language-server-nodejs.

Example Docker configuration:

"language.dockerfile.languageServer.command": "docker-langserver",
"language.dockerfile.languageServer.arguments": ["--stdio"],

Go

Go language support depends on the go-langserver by SourceGraph, which provides language support for Go. Follow their installation instructions as this language server is not bundled out-of-the-box with Oni.

go-langserver must be available in your PATH. You can override this by setting the language.go.languageServer.command configuration value.

Example Golang configuration:

// language server configuration
"language.go.languageServer.rootFiles": [".git"], // In a git repository
"language.go.languageServer.command": "go-langserver",
"language.go.languageServer.arguments": ["--gocodecompletion", "--freeosmemory", "false"],

Haskell

Haskell language support is provided via the haskell-ide-engine.

Example Haskell configuration:

"language.haskell.languageServer.command": "hi",
"language.haskell.languageServer.arguments": ["--lsp"],
"language.haskell.languageServer.rootFiles": [".git"],

Java

Java language support is provided via the eclipse.jdt.ls. The lastest version can be found on this link. Decompress the file and put the folder on the PATH (for example C:\dev\jdt-language-server-latest).

Configuration for Oni on Windows using Java 8:

"language.java.languageServer.command": "C:\\dev\\java\\jdk1.8.0_161_i586\\bin\\java",
"language.java.languageServer.arguments": [
    "-Declipse.application=org.eclipse.jdt.ls.core.id1",
    "-Dosgi.bundles.defaultStartLevel=4",
    "-Declipse.product=org.eclipse.jdt.ls.core.product",
    "-Dlog.protocol=true",
    "-Dlog.level=NONE",
    "-noverify",
    "-Xmx1G",
    "-jar",
    "C:\\dev\\jdt-language-server-latest\\plugins\\org.eclipse.equinox.launcher_1.5.0.v20180207-1446.jar",
    "-configuration",
    "C:\\dev\\jdt-language-server-latest\\config_win",
    "-data"
],
"language.java.languageServer.rootFiles": ["pom.xml"],

JavaScript and TypeScript

JavaScript and TypeScript support is enabled out-of-the-box using the TypeScript Standalone Server. No setup and configuration is necessary, however, you will get better results if you use a tsconfig.json or a jsconfig.json to structure your project.

JavaScript and Flow

If you would like to add flow support (a static type checker for javascript), you will need to add the flow-language-server, This can be done by running yarn global add flow-language-server or npm install -g flow-language-server, then adding the following lines to your oni config.js

  'language.javascript.languageServer.command': 'flow-language-server',
  'language.javascript.languageServer.arguments': ['--stdio'],

JavaScript and Vue

To add language support for vue, the javascript framework and it's filetype, you will need to complete the following steps.

1. Run npm install -g vue-language-server
2. Add the following to your config.js

 'language.vue.languageServer.command':'vls'

Lua

Lua language support is provided via the lua-lsp.

Example Lua configuration:

"language.lua.languageServer.command": "lua-ls",
"language.lua.languageServer.rootFiles": [".git"],

Python

Python language support depends on pyls by Palantir, which provides language support for Python. Follow their installation instructions as this language server is not bundled out-of-the-box with Oni.

pyls must be available in your PATH. You can override this by setting the language.python.languageServer.command configuration value.

Reason and OCaml

Oni comes with ocaml-language-server out-of-the-box, however, make sure you have the other pre-requisites installed and that merlin is configured properly.

Ruby

Ruby language support is provided via the language_server-ruby.

Example Ruby configuration:

"language.ruby.languageServer.command": "docker",
"language.ruby.languageServer.arguments": [
  "run",
  "mtsmfm/language_server-ruby",
],

Rust

Rust language support is provided via the rls an example configuration is

// Language Support - Rust
"language.rust.languageServer.command": "rustup",
"language.rust.languageServer.arguments": ["run", "stable", "rls"],
"language.rust.languageServer.rootFiles": ["Cargo.toml"],