Customize validator and generator using workspace.ConfigurationProvider

[borisbrodski]

My DSL needs some project dependent configuration, like for example:

• name of an abstract class to extend my generated java class from
• some limits to stuff

The settings should work the same: in LS (VS Code/Eclipse/....) and in CLI generator.

I looked into using workspace.ConfigurationProvider for this purpose. The settings could be declared and described in package.json and the values places then into .vscode/settings.json.

But settings.json doesn't get loaded while generating code with CLI. Other IDEs would probably also not be capable of reading
settings.json and providing LS with my custom configuration.

Is there some working solution/example of how to deal with settings in Langium DSLs?

Or sould I implement my own configuration, which is independend from LS and VSCode features?

Thank you!

[msujew]

Hey @borisbrodski,

the configuration you're talking about is essentially a compiler configuration. Most programming languages (like TypeScript's tsconfig.json) feature a separate configuration format for that. The CLI and the language server would both read that file to determine the compiler options.

In general, you shouldn't use compiler options as language server configuration items. As you've already seen, reading those in a CLI is effectively impossible and there's even one more important argument: The language server provides language services to an IDE. Therefore, unless absolutely necessary, only language service related configurations should appear as configuration items (i.e. stuff like whether certain code lenses should appear, etc.).

[borisbrodski]

Hey Mark,

thank you for quick response!

This makes a lot of sense. How would you implement loading mydsl-config.json files?

• Create a custom WorkspaceManager, that loads my-config.json configuration files overwriting DefaultWorkspaceManager.loadAdditionalDocuments() method and add these as LangiumDocuments?

I would rather write an additional service like MySettingsProvider, but I found no way to access the workspace paths used to initialize WorkspaceManager.

I have following in my main.ts:

    const workspaceFolder: WorkspaceFolder = {
        name: 'MyDSL Workspace',
        uri: URI.file(path.resolve(workspaceDir)).toString()
    };
    await workspaceManager.initializeWorkspace([workspaceFolder]);

[msujew]

It's likely much more reasonable to have a MySettingsProvider that works with the json file directly. Stuffing the data into a LangiumDocument will be quite difficult, as those are reserved for documents of your DSL.

I found no way to access the workspace paths used to initialize WorkspaceManager.

You can listen on the initialization of the language server, see

https://github.com/eclipse-langium/langium/blob/main/packages/langium/src/lsp/language-server.ts#L46

The params contain the workspace folders of the language client. Alternatively, you can create your own WorkspaceManager that initializes the MySettingsProvider with the provided workspace folders.