[meta] Add var-coloring code from Bikeshed?

[tabatkins]

A feature I appreciate, particularly in WHATWG-style specs with their heavy-algorithmic style, is the ability to click on a variable and get all of its instances highlighted in the same color, to easily track where the var is used in an algo. This works on all the non-HTML whatwg specs, since they're all Bikeshedded, but Wattsi doesn't have the same functionality.

This is done entirely in CSS/JS, so it should be trivially exportable to Wattsi; see the code at https://github.com/tabatkins/bikeshed/blob/main/bikeshed/unsortedJunk.py#L303. The only thing you might need to change is to remove the check that bails if the variable is document-global; I don't think the HTML spec annotates its algorithms with a useful scoping container (like Bikeshed pushes you towards with the algorithm attribute), so they're all document-global. That'll be fine, it'll just mean that coloring a variable in one algo might result in other algos starting out with some of their variables colored as well.

[domenic]

This works on all the non-HTML whatwg specs, since they're all Bikeshedded, but Wattsi doesn't have the same functionality.

Unfortunately it does not; it only works on specs that have used those <div algorithm> wrappers you mention. Compare:

• https://fetch.spec.whatwg.org/#concept-header-list-get-structured-header
• https://streams.spec.whatwg.org/#readablestream-set-up

I'd be hesitant to port this feature over without such scoping... I don't think we have any experience with whether that'd be fine, as you claim, or annoying and confusing, as I might expect.

[domenic]

Heh, see https://github.com/tabatkins/bikeshed/blob/c504886555dee3381c5b56eb55c297196431a0d6/bikeshed/unsortedJunk.py#L355-L357:

            // Not highlighting document-global vars,
            // too likely to be unrelated.
            if(algoContainer == null) return;

[tabatkins]

Right, Bikeshed has the algo container scoping as a feature already, so I consider it reasonable to lean on that.

But in the absence of that as a feature in Wattsi, I (personally) think it's more valuable to have highlighted vars than to avoid over-highlighting vars. A week or two ago I was looking over an algo and had to read very carefully to see that a particular variable wasn't used anywhere else in the algo, an operation that would have taken half a second and been extremely reliable if I'd been able to just click on it and see if anything else colored.

[jmdyck]

Can this be closed now that #11392 has been merged?

[keithamus]

Yes I think so. If anyone disagrees we can always reopen. Thanks!