Implement Document Symbols Request

[aslakhellesoy]

🤔 What's the problem you're trying to solve?

See the outline of a Gherkin Document in my editor

✨ What's your proposed solution?

Implement Document Symbols Request.

⛏ Have you considered any alternatives or workarounds?

Yes - implementing it directly in a VSCode Extension. This would limit usage to VSCode users - other editor users would not get the functionality. See cucumber/vscode#111 (review)

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[10xtechie]

@aslakhellesoy ,
Which keywords (Scenario, Rule) of Cucumber should we provided by this new service?

[aslakhellesoy]

We should look for the following keywords: Feature, Rule, Scenario, Examples. We might also want to add Given/When/Then/And (steps), but let's omit that for now.

I think you should add a new getGherkinDocumentSymbols(gherkinSource: string): readonly DocumentSymbol[] function in src/service/getGherkinDocumentSymbols.ts.

I recommend you start by writing a failing test that:

• calls getGherkinDocumentSymbols(gherkinSource) with a simple Gherkin source
• verifies that the returned document symbols are what you expect.

Look at https://github.com/cucumber/language-service/blob/main/test/service/getGherkinDiagnostics.test.ts for inspiration.

You might be able to implement the function with the help of the walkGherkinDocument function. It's already used in some of the other src/service/*.ts functions.

[aslakhellesoy]

Hi @10xtechie - have you made any progress on this? I have an implementation of this that I haven't pushed - I wanted to give you a chance to complete yours first :-)

[10xtechie]

@aslakhellesoy ,
I am sorry for this late reply as I was tied up. Thanks for awaiting my implementations. I have just pushed my initial changes. I am in two minds: should LSP return the array of Document Symbols with custom tree format or should it return Document Symbols using Tree View API Basics.
Please provide me with your feedback; also not sure why the current test is failing.