Add server commands

[Jarlakxen]

Implemente #27. I putted some of the code in a companion object just to keep the ScalaLanguageClient class small.

[laughedelic]

Hi @Jarlakxen. Is this a work in progress?

[Jarlakxen]

Hi @laughedelic! The work is done for clearIndexCache and resetPresentationCompiler. I noticed a scalafixUnusedImports which is not mentioned in #27. Would you like to open a new issue? or I can try to do it all together.

[laughedelic]

Yes, it's better to add all available commands here. There's actually one more command: sbtConnect.

[laughedelic]

I'm just curious, what do you have there, why do you need to ignore it in every project?

[laughedelic]

Remove debug logging before merging, please. Btw, you can see it in the Atom logs anyway.

[laughedelic]

I think that all this can be drastically simplified: once you got supportedCommands, you can just iterate over them and add each of them.

There's a bit tricky part about command names. See Atom docs:

Command names must follow the namespace:action pattern, where namespace will typically be the name of your package, and action describes the behavior of your command. If either part consists of multiple words, these must be separated by hyphens. E.g. awesome-package:turn-it-up-to-eleven. All words should be lowercased.

• We should use either package name (ide-scala) or server name (metals) as the namespace prefix here (by the way, all this is specific to metals at the moment)
• Command name has to be transformed from camelCase to snake-case (Atom will take care of formatting it nice for the command palette)

Here's a draft:

supportedCommands.foreach { cmd =>

  val cmdName = "[A-Z]".r.replaceAllIn(cmd, { "-" + _.group(0).toLowerCase() })

  Atom.commands.add("atom-text-editor", s"metals:${cmdName}", { _ => 
    server.connection.executeCommand(
      new ExecuteCommandParams(command = cmd)
    )
  })
}

@Jarlakxen what do you think about this approach?

[Jarlakxen]

From what I understand that could work for clearIndexCache, resetPresentationCompiler and sbtConnect but not for scalafixUnusedImports. If that is correct, a solution could be define a whitelist of commands without special treatment like clearIndexCache, resetPresentationCompiler and sbtConnect and implement scalafixUnusedImports in other place.

[laughedelic]

I'm not sure I get it, why does scalafixUnusedImports need a special treatment?

[Jarlakxen]

I saw this part of the code https://github.com/scalameta/metals/blob/master/metaserver/src/main/scala/scala/meta/languageserver/ScalametaServices.scala#L367 and OrganizeImports.removeUnused(params.arguments, symbolIndex) use params: ExecuteCommandParams. That arguments contains a TextDocumentIdentifier.
Maybe I didn't understand the functionality but from what I understand I need to pass a reference to the file from which I want to remove the unused imports.

[laughedelic]

I see. I think this is also solvable, but let's keep things simple for now and just skip this command:

• the VS Code extension for metals doesn't have it either
• you would normally use it through the code action, so it's won't be missing

[laughedelic]

Looks fine, except the extra formatting changes. Could you revert them? I'm going to setup a scalafmt config later, so all code will have consistent formatting. Until then I'd like to keep PR changes to the minimum.

It's also strange that the CI is failing, I don't understand what is the problem.. 🤔

[laughedelic]

@Jarlakxen I just tried it out with the latest published server and it seems to work fine. At least I see that it receives the command request. Let's merge it!