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
  • JavaScript and TypeScript
    • JavaScript and Flow
    • Javascript and Vue
  • C/C++
  • C#
  • Go
  • Python
  • Reason and OCaml

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

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'

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.

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.

Known Issues

• There is no Windows support at the moment - this is being tracked by sourcegraph/go-langserver#113.

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.