Wolfram Language Server

by kenkangxgwe and hxianglong

Table of Contents

Wolfram Language Server

Wolfram Language Server (WLServer) is an implementation of the Microsoft's Language Server Protocol (LSP) for Wolfram Language. This server is implemented in Wolfram Language itself.

Our current goal is to provide the experience as good as the Mathematica FrontEnd with addition power from the editor.

We have provided the client-side code for VS Code here, which is based on some slight modifications of Microsoft's LSP example. If you are using other editors supporting LSP, some adaptation to the client would certainly work too.

Installation

Wolfram Mathematica (11.2 or higher ¹) or Wolfram Engine (12.0 or higher).

Use git to clone this repository.

git clone https://github.com/kenkangxgwe/lsp-wl.git

Install the dependent paclets with the correct versions (currently 0.15) from the Wolfram kernel / Mathematica. (This will cost some time for the first time) :
```
PacletInstall["AST", "UpdateSites" -> True]
PacletInstall["Lint", "UpdateSites" -> True]
```
Install the client. Currently, we provide the VS Code extension on Visual Studio Marketplace: Wolfram Language Server

Run the Server

Clients can start the server by running the init.wls file from Wolfram Mathematica executables

wolfram -script /path/to/lsp-wl/init.wls [args]
# or
wolframscript -f /path/to/lsp-wl/init.wls [args]

The posible arguments for the server are

--help, -h to print help information.
--socket=port to assign the port to which the server will connect. (Default: 6536)
--tcp-server=port to assign the port at which the server will start. (Default: 6536)
--pipe=pipename to specify the pipe name for the server to connect to.
--log=level, -l level to specify the logging level of the server. (Levels: error, warn, info, debug. Default: info)
--test, -t to run the unit test for the server.

If you want to run the server from Mathematica you can use the following code.

initfile = "/path/to/lsp-wl/init.wls";
args = {};
Block[{$ScriptCommandLine = Prepend[args, initfile], Quit = Function[{}, Throw[Null]]},
    Catch[<< (initfile)]
];

This is a good way to see the results from the unit tests.

Features

DocumentSymbol: You may typeset your package in the same way that Mathematica FrontEnd handles it: a cell begins with two lines of comments, where the first line specifies the style of the cell and the second line names it. So you may get the outline structure of the file.
```
(* ::Title:: *)
(*Title of the file*)

(* ::Section:: *)
(*Section 1*)
```
Hover: Provide documentations for functions and variables from the System` context, such as String and $Path, the MessageName and the special numerical literals with ^^ or *^.
Completion: The completion is shown by the client automatically. Functions and system variables from the System` context that matches the input would be displayed. To enter an unicode character, you may use the leader key \ followed by the alias just like esc in Wolfram FrondEnd. E.g., <esc>a in the FrontEnd is input as \a in the editor and the server will show you the available completions.
Completion Resolve: Further information (such as documentation) would be provided for the items in the list.
Diagnostics: Syntax error would be underlined. This feature is powered by Brenton's AST and Lint paclets, thank you @bostick.
Definition / References / DocumentHighlight: It is now able to look up the definition and references of a local variable in a scope such as Module or pattern rules.
Document Color / Color Presentation: Both Named Colors and Color Models with constant parameters are able to show and modify.
(Experimental, may have performance issues.)

This is an early release, so more features are on the way. Notice that, syntax highlight will not be provided as long as it is excluded in the LSP, but I believe there are plenty of good Mathematica highlighter available for your editor.

Here is a full list of LSP features.

Contribute

Design Principles

The files are located according to its context name. The init.wls is the entry script that parses the commandline arguments, loads packages and starts the server.
We implemented an stateless server in WolframLanguageServer`Server` that will parse and handle the messages.
DataType` is a simple type system now extracted as a independent package in the Matypetica library that supports pattern test on every field of a class. The operations on the objects are designed to be immutable.
WolframLanguageServer`Test`* stores the unit tests for some of the functions.

Todo list

It will be nice if you want to make a contribution to the following topic.

Our server-client communication only supports Socket with TCP protocol. We tried to use ZMQ_Stream protocol and SocketListen[] to enable concurrency, but it fails to send responses back to the client.
It will be helpful to implement a stdio channel, ~~so that the Mathematica earlier than 11.2 will also be supported,~~ but it is really hard to expose the stdin channel. Hope this will be dicussed in future release of Wolfram kernel.
More editor clients are needed. You can feel free to open a repository and create a pull request to add the clients in README.md once your client is released.
Thanks to Brenton's AST and Lint paclets, we are able to parse the code and extract useful information. If you have an idea about how to use these fantastic syntax tools to help the language server add more features, please send us issues or pull requests.

If you want to help us with this project, feel free to fork and create a pull request. Do not forget to add unit tests if possible.

Donations 💵

If you really like this project, please donate to us! $5 (or equivalently ￥35). A cup of coffee ☕ would certainly brighten our day! Your donation would be the motivation for us to move forward, thanks in advance 😄.

Paypal: qwe95123@126.com
Alipay (With QRCode): 13916018006

Footnotes

[1] SocketListen[] is used for server-client communication, which is introduced since 11.2. ^

lingqi-su/lsp-wl