[Feature Request] Add separator lines in Dockerfile for multistage build

[ras0q]

If the extension could provide hints for separating each stage into sections, it would improve readability without the need for users to explicitly include comments separating the stages.

Slidev offers a feature similar to this.
https://sli.dev/features/vscode-extension

before	after

[benwaffle]

Yeah, this would be nice. IntelliJ IDEs do this:

[rcjsuen]

I'm not sure if the language server can do anything about this. @bwateratmsft Does VS Code have APIs to draw horizontal lines in the editor?

[bwateratmsft]

@rcjsuen We could maybe use CodeLens although that's not really the intended purpose. I think the closest thing would be folding ranges, but that's already covered in issue #230.

I'll resolve this as a duplicate of #230. @ras0q @benwaffle if you think #230 is too different from what you're looking for, can you file an issue on VSCode to support horizontal lines?

[benwaffle]

Can do. Are you only interested in doing this via LSP? As far as I know, VSCode extensions can do custom drawing on the editor.

[bwateratmsft]

Yeah, the LSP would be the right way to do this. Do you have any info on that custom drawing capability?

[benwaffle]

I know for certain you can do it in monaco, the editor library from vscode - https://microsoft.github.io/monaco-editor/playground.html?source=v0.52.2#example-interacting-with-the-editor-listening-to-mouse-events

So I assumed you can do the same thing via an extension

[rcjsuen]

So I assumed you can do the same thing via an extension

Thanks for that example, @benwaffle. Looks like you can draw random lines with Monaco's changeViewZones API. I'm not familiar with the decorations API in VS Code so not sure if we can replicate the same thing here or not (even if we think outside the "language server box").

[bwateratmsft]

VSCode's extension APIs don't give direct access to the Monaco framework. There are webviews where you can do whatever you want, but the text editor isn't a webview in the sense that it cannot be extension-controlled, except through the APIs that VSCode offers.