Export LSP services via dedicated ESM export

[msujew]

Currently, our LSP services (which rely heavily on the vscode-languageserver package) are exported through the main langium export. While this makes creating language servers very easy, it leads to a lot of unnecessary imports for adopters that don't want to build a language server, thereby increasing bundle size.

The long term plan (likely version 3.0, as it's a major breaking change) would be to export the LSP related services through a langium/lsp export. That way, adopters can choose to not to include those services.

[cdietrich]

@sailingKieler will the be a new preview version to test this out?

[msujew]

@cdietrich Yes, I'll probably release a next version today/tomorrow.

[msujew]

@cdietrich New next release is available on npm :)

[cdietrich]

@msujew what is the replacement for
ServiceRegistry.getServices(uri) to obtain Services with lsp?

[sailingKieler]

@msujew what is the replacement for ServiceRegistry.getServices(uri) to obtain Services with lsp?

@cdietrich for now you could do it the following way:

    const service: LangiumCoreAndPartialLSPServices = services.ServiceRegistry.getServices(uri);
    service.lsp?...

The LangiumCoreAndPartialLSPServices is available via langium/lsp.
Feel free to propose an alternative pattern. 😉

[cdietrich]

ok so i need to downcast ;)

[sailingKieler]

ok so i need to downcast ;)

Yes. In case the LSP-related parts are available - which is the typical case - you get them via the ServiceRegistry.
It's just that we can't (don't want to) reference the LSP-related Symbols from the ServiceRegistry being part of the core components.

[spoenemann]

In a context where you know that LSP services are loaded, you can simply cast to LangiumServices.