Ada Language Server

This repository contains a prototype implementation of the Microsoft Language Server Protocol for Ada/SPARK.

Current features:

• GNAT project files
• Code completion
• Go to definition
• Find corresponding references
• Document symbol search

We also provide Visual Studio Code extension as .vsix file.

Install

You can install binary image or build language server from sources.

To install binary image download an archive corresponding to your OS and unpack it somewhere. You will find ada_language_server inside unpacked folder. We provide binaries for

• Linux x86_64 - take linux.tar.gz
• Window 64 bit - take win32.zip
• Mac OS X - take darwin.tar.gz

To build is from source install dependencies and run

make

It will build .obj/server/ada_language_server file.

Dependencies

To build the language server you need at least a version of the GNAT compiler, and the Libadalang library to be built and available via the GPR_PROJECT_PATH.

To run the language server you need gnatls (parts of GNAT installation) somewhere in the path.

Usage

The ada_language_server doesn't require/understand any command line options.

Debugging

You can activate traces that show all the server input/output. This is done by creating a file $HOME/.als/traces.cfg with the following contents:

ALS.IN=yes > inout.txt:buffer_size=0
ALS.OUT=yes > inout.txt:buffer_size=0

When this is present, the ALS will generate a file $HOME/.als/inout.txt which logs the input received and the output sent by the language server.

Testsuite

See more about the project testsuite in a separate document.

Supported LSP Server Requests

General Requests

Workspace Requests

Synchronization Requests

Text Document Requests

Protocol extensions

The Ada Language Server supports some features that are not in the official Language Server Protocol specification. See corresponding document.

How to use the VScode extension

For the moment, this repository includes a vscode extension that is used as the reference extension for this implementation.

You can try it by running:

code --extensionDevelopmentPath=<path_to_this_repo>/integration/vscode/ada <workspace directory>

You can configure the GNAT Project File and scenario variables via the .vscode/settings.json settings file, via the keys "ada.projectFile" and "ada.scenarioVariables".

You can set the character set to use when the server has to use when reading files from disk by specifying an "ada.defaultCharset" key. The default is iso-8859-1.

You can explicitly deactivate the emission of diagnostics, via the "ada.enableDiagnostics key. By default, diagnostics are enabled.

Here is an example config file from the gnatcov project:

{
    "ada.projectFile": "gnatcov.gpr",
    "ada.scenarioVariables": {
        "BINUTILS_BUILD_DIR": "/null",
        "BINUTILS_SRC_DIR": "/null"
    },
   "ada.defaultCharset": "utf-8",
   "ada.enableDiagnostics": false,
}

Integration with LanguageClient-Neovim

If you want to integrate the Ada Language Server into Neovim, you can use the LanguageClient-neovim.

You'll have to install the Ada Language Server manually somewhere on your computer, and then you can add the following line to your init.vim file:

" replace the path below with the proper path to the ada_language_server executable
let g:LanguageClient_serverCommands = {
    \ 'ada': ['path/to/ada_language_server'],
    \ }
" if you already have LanguageClient_serverCommands, just add a line for ada.

To configure the Ada Language Server for a specific workspace/project, you can use the .vim/settings.json file. It is mandatory as soon as you want to use a specific .gpr project file.

This is the way to specify a project file, eg. you cannot open a project file another way.

Here is an example of a settings file:

{
    "ada.projectFile": "project.gpr",
    "ada.scenarioVariables": {
        "GLFW_Version": "3",
        "GLFW_Lib": "-lglfw",
        "Windowing_System": "x11"
    }
}

The location where the .vim folder is located will determine the relative path of the project file (so no need to prefix with ..). When vim is opened in the folder containing this .vim directory, it will use those settings for the language server even for files which might have nothing to do with that specific project, so this needs to be taken into account. Ultimately what this means is that the configuration is determined by where you open vim.

Integration with emacs lsp-mode

The configuration for each project can be provided using a .dir-locals.el file defined at the root of each project.

The scenario variables should be declared in your .emacs or any loaded Emacs configuration file.

(defgroup project-build nil
  "LSP options for Project"
  :group 'ada-mode)

(defcustom project-build-type "Debug"
  "Controls the type of build of a project.
   Default is Debug, other choices are Release and Coverage."
  :type '(choice
          (const "Debug")
          (const "Coverage")
          (const "Release"))
  :group 'project-build)

Your .dir-locals.el in the project root should be similar to:

((ada-mode .
  ((eval . (lsp-register-custom-settings
      '(("ada.scenarioVariables.BINUTILS_SRC_DIR" project-binutils-dir)
        ("ada.scenarioVariables.BUILD_TYPE" project-build-type "Release"))))
   (lsp-ada-project-file . "/home/username/project/project.gpr"))
  ))

The lsp-mode provides built-in support for the ada_language_server and defines default customizable configuration values in the lsp-ada group that can be edited similarly to lsp-ada-project-file in the example above.

Maintainer

@MaximReznik.

Contribute

Feel free to dive in! Open an issue or submit PRs.

License

GPL-3