[StickyScrolling] Introduce enhancement point

[Christopher-Hermann]

In order to implement editor/language specific sticky lines provider, a new extension point is introduced.

See issues:

• Sticky scrolling resets on comment lines #2338
• [Sticky scrolling] Commented-out code is being incorrectly recognized #2128
• Sticky scrolling should allow to be fed by language-specific info/annotations #1950

The idea is that the package of the extension point is internal in the first place.

1. We from SAP will provide a extension for the SAP language ABAP.
2. In [Help Needed] Implement provider for sticky scrolling in JAVA/JDT eclipse-jdt/eclipse.jdt.ui#1851 we provide a implementation for JDT.

If both implementation works as expected, the API is most probably stable and we can change to package of the extension point to public usage.

[BeckerWdf]

so we would remove the "x-internal:=true" part to make this "real" API once we are confident enough?

[Christopher-Hermann]

Yes, that would be the idea. But I'm not sure if this is the right approach or if this is a good idea.

[github-actions]

Test Results

0 files   -  1 821  0 suites   - 1 821   0s ⏱️ - 1h 35m 36s
0 tests  -  7 719  0 ✅  -  7 489  0 💤  - 228  0 ❌  - 2 
0 runs   - 24 318  0 ✅  - 23 567  0 💤  - 749  0 ❌  - 2 

Results for commit b5eec35. ± Comparison against base commit 55481d3.

♻️ This comment has been updated with latest results.

[mickaelistria]

Can this share a lot of code with the folding range?
Instead of a new dedicated provider API, could it be implemented through reconciler and annotations (just like Folding) ?

[Christopher-Hermann]

Can this share a lot of code with the folding range? Instead of a new dedicated provider API, could it be implemented through reconciler and annotations (just like Folding) ?

investigated the possibility, and it appears that annotations can likely be reused for sticky scrolling functionality. We could attach a depth attribute to each line that is a potential sticky line candidate. The sticky line handler could then determine which line should be attached based on the scroll index and the depth specified in the annotation.

However, utilizing annotations may reduce flexibility, which can be beneficial in certain scenarios. For example, if you want to apply different styles to the sticky lines or even add text that is not originally part of the editor, relying solely on annotations could be limiting.
See this example where I added a custom text with custom styling:

[danthe1st]

However, utilizing annotations may reduce flexibility

I guess it would be possible to use folding annotations by default (if present, otherwise use indentation as done currently) and still allow overriding the sticky scrolling functionality?