Tag: lsp

Progress has been a bit scattered, but steady. The shell now supports theming and Rubberduck 3 will ship minimally with light/blue, light, dark, and dark/blue themes, currently essentially copied and adapted from Visual Studio and VS Code color palettes. I’ve hit a bump on the road trying to get fancy with the window chrome controls, but I’m going to be putting that aside if I don’t get to a satisfying solution soon.

With the envisioned chrome, the title bar would blend with the menu bar, and the window commands at the right would also match the theme. Obviously that’s far from a showstopper!

With theming out of the way, the editor shell looks fabulous but is still far from completed. The client area where the giant ducky outline logo is currently shown, is where the editor actually needs to have its docking panels and document tab host – the outline logo will have to be moved there if it’s to be visible at all when everything is done.

Because of license compatibility issues, the AvalonDock library which would be the natural go-to option since the actual editor tabs will be AvalonEdit controls, cannot be used. As an alternative with a compatible license, rather than developing our own docking panels and MDI layout, we’ll be using the Dragablz library and its Dockablz layout panels.

Document Types

The prototype 6 months ago only covered one aspect of the editor – the code editor. But Rubberduck 3.0 will need to have the ability to edit more than just VBA code.

In VBA a project is embedded in its host document and consists of the VBProject component modules; in RD3 a VBA project lives on disk, and Rubberduck knows what project files are to be synchronized with the VBE, but there’s nothing stopping it from being able to include additional files which don’t synchronize back to the VBE but can be useful for development.

Plain Text

RD3 will create a .rdproj (“Rubberduck Project”) file in the workspace folder. That file is going to be a plain text (JSON) file, and we want the editor to be able to open and edit it. Eventually there might be a dedicated language server that understands JSON syntax as a language (and then .rdproj files can get syntax highlighting, section folding, completion, etc.), but that will not be a priority at first – what will be, is just to ensure we can load such text files in the editor.

Markdown

Text files with formatting; markdown (.md) format is essentially today’s tech for what used to be done with RTF – in other words, they’re formatted text files, but instead of an obscure RTF syntax it’s all done with plain ASCII characters, just like on GitHub, Stack Overflow, and Jira.

And this is great news, because then having the ability to render markdown in XAML means we get to format other things that used to be strictly plain text – like message boxes:

The language server can also supply such formatted content for tooltips and parameter info, so there’s a non-zero chance @description annotations in RD3 can even honor such formatting when present in docstrings.

The editor shell will support editing and rendering markdown documents, so your project can include a README.md file that you can edit and preview directly in the editor.

It also makes a nice document type to display a startup/”welcome” tab that describes the latest features after an update, again a bit like Visual Studio does.

VBA Code

Text files that the editor understands to be Classic-VB code files (this will have to be based on their respective file extensions) that contain the code for VBProject components that may or may not belong to the workspace of the project that’s in the VBE. Because we’re working off exported files and a .rdproj tells us what libraries are referenced and where to go find what modules for that project, we can now also edit “orphaned files”, as we are no longer constrained to editing code files that belong to the host project!

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.rdproj, and consequences

Among the many challenges in RD2, was the fact that we wanted to avoid cluttering our users’ files with any kind of non-code metadata. For example at one point an idea was floated around for hijacking just one single module and having it contain nothing other than commented-out project metadata. Or perhaps carrying this metadata in a file alongside the host document. None of these approaches were going to be enjoyable to use, so instead RD2 dropped the idea of having any per-project configurations, because in RD2 the host document is the single source of truth.

That’s one of the many things changing with v3.0: because the truth has moved outside of the host document and into workspace folders, we now have a per-project physical location to put Rubberduck metadata in.

If we are to hope for feature parity with 2.x, the add-in needs to tell the language server about the project, including the location of referenced libraries. In RD2 we would simply acquire the project references and proceed to extract the types and members, but the language server in RD3 knows absolutely nothing about COM and does exactly zero interop with the VBIDE – so we needed a way to pass the information along without twisting the LSP in ways that would make it impossible for clients other than the Rubberduck Editor to use our language server. Not that it’s a requirement, but the idea is to do things right, not just to make it work for our purposes: if we strictly adhere to the language server protocol (LSP) specifications, then at least in theory it would be simple to write an addin client for any other LSP-capable editor, including VSCode. It’s not a target to write such a client, but having the possibility to do it is.

So rather than coming up with a way to serialize that information and pass it to the server through custom initialization parameters (the protocol defines an “additional data” dictionary that could theoretically be used for this), the addin will generate and maintain a .rdproj file whenever it exports source files to the workspace.

This “Rubberduck Project” file will contain basic information such as the Rubberduck version, a URI for the project root, and then a URI for each library reference (or perhaps just a ProgID string? Or a GUID representing its CLSID? All of the above? 🤔 TBD) and another URI for each module in the project. This isn’t completely final because it’s pretty much just about to be implemented, but the idea would be to end up serializing to a file that would look something like this:

{ 
  "rubberduck" : "3.0.0",
  "project" : {
    "references" : [
      "file://path/to/vba7.dll",
      "file://path/to/host.tlb",
      "file://path/to/library"
    ],
    "modules" : [{
      "name" : "ThisWorkbook",
      "super" : "Workbook",
      "uri" : "file://relative/path"
      }, {
      "name" : "Sheet1",
      "super" : "Worksheet",
      "uri" : "file://relative/path"
    }, {
      "name" : "Module1",
      "uri" : "file://relative/path"
    }]
  }
}

Of particular note are the document module supertypes, which is information RD2 manages to collect from in-process ITypeInfo pointers that the language server in RD3 isn’t going to have access to, by virtue of running in an entirely separate process.

This means the RD3 addin has the following responsibilities:

• Connect/Disconnect the VBIDE host;
• Import/Export modules into the VBE and workspace folders;
• All debugger functionalities;
• Execute Rubberduck unit tests (VBA code);
• Collect any ITypeLib/ITypeInfo metadata that can be collected for a VBProject.
• Start/Shutdown the Rubberduck Editor;

That’s quite a lot already, and these bullet points already make it clear that the single responsibility of the Rubberduck.dll library must encompass every single interaction with the VBIDE, including the native Office CommandBar controls.

It’s a lot already, but that’s the complete extent of it – which means RD3 connects and loads as a VBIDE addin when the VBE starts up, …but then it doesn’t need to resolve the entirety of Rubberduck at startup, which means a splash screen isn’t even warranted here because we’re completely loaded and good to go in the blink of an eye, and it’s (mostly) not even because of dotnet 7! In other words, RD3 restores the Alt+F11 performance and sharpness you know and love.

The last bullet in the list is why: the VBE loads the RD3 VBIDE add-in, and uses JsonRPC messages to communicate with the Rubberduck Editor process. The editor in turn starts the language server, and each process runs in its own separate silo while running periodical “health checks” to ensure there’s still a client process on the other end – if a server loses its client, it shuts down; if a client loses its server, it can just start a new one and carry on without much disruption.

The addin becomes a lightweight launcher that extends the VBE by exposing menu commands that pop an “About” box, or start the Rubberduck Editor app. It wouldn’t be outside of its scope to also launch update and telemetry servers, and since the settings are shared between all processes, a command to bring up Rubberduck settings could be in-scope as well.

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Next Steps

Work on the Rubberduck Editor is only getting started! Without thinking too far ahead, here’s what’s to come:

• Window chrome controls and resize thumb
• Put everything together to serialize .rdproj
• “New Rubberduck Project” dialog UI
• Import/export VBProject commands
• Document tab host
• Docking panels, side/tool panels
• “Welcome” markdown document tab
• Open/close text and other document types
• Save, save as commands
• Settings dialog UI
• About dialog UI

And then that’s just what can move forward to completion in the Rubberduck Editor part without the server side – but we’ll cross that bridge when we get to the airport, as they say.

Both telemetry and update server applications have their skeletons done and can be started and debugged just like the language server.

Update Server

By running this server separately from the rest, we can get RD3 to update itself without needing to leave the VBE or close the host application and everything you’re working on: if the update server is so configured, it can tell the addin to shut down, which in turn shuts down the Rubberduck Editor, which shuts down the language server.

At that point none of the Rubberduck libraries are in use, and the update server can overwrite them with a newer version before instructing you to manually load the Rubberduck addin which again starts pretty much instantly.

This only requires that we package and ship the update server separately from the addin… kind of like how Visual Studio does.

Telemetry Server

One of the things we want RD3 to address, is just getting basic feature usage information so there’s data out there to help diagnose and prioritize any issues. Logging in RD2 is pretty extensive and verbose already, but it’s very organic and missing in some places; in RD3 logging is built into the base classes for every server-side handler, and with requests coming in asynchronously we need a better way to track what entries belong to which request, and this is exactly what telemetry logs do. The telemetry server will be fully configurable and will never transmit any PII information anywhere. As it handles telemetry events, this server serializes and enqueues telemetry payloads; the queue can then be reviewed, filtered, manually transmitted or cleared, or it can be configured to transmit periodically in batches – the receiving end will be hosted on api.rubberduckvba.com, and there’s a storage concern that may require severely limiting how much data we can keep around and aggregate (probably going to need to sample the data / reject most payloads!), but that’s a concern for another day.

Ultimately the goal is to surface the entire dataset through some explorable dashboards, charts, and tables on the website, so everyone can see what data is being collected: exactly none of it is going to be a secret.

The language server will be able to send language-level telemetry data, on top of everything else that’s useful for debugging. Aggregating this data would allow us to expose how our users are using VBA, from simple metrics like the number of modules in a project to interesting tidbits such as the average number of expressions in a conditional, or what kind of loop constructs people use the most (e.g. While…Wend vs Do…Loop), whether our users declare and fire custom events, implement interfaces, …anything we can think of, really. This obviously isn’t a priority, but it’s been on my mind ever since I heard the Microsoft Excel product team mention they haven’t got the slightest idea of what people do with VBA: seen by the right eyes this data could, ironically, eventually possibly contribute to achieving feature-parity in the VBA alternatives being developed by Microsoft… or rest the case that VBA cannot be taken away because what people do with it involves things that aren’t going to be supported in prospective so-called alternatives (looking at you, OfficeJS).

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Development of Rubberduck 3.0 continues, stay tuned for updates, as I’ll be posting here all along the journey.