Expansion Section 5.2.1, step 7: need clarification

[daenney]

I'm working through the expansion algorithm, and I'm stuck on step 7. I don't understand what it wants me to do.

The text of step 7, as of 2025-02-28 (W3C Recommendation 16 July 2020), reads:

If active context has a previous context, the active context is not propagated. If from map is undefined or false, and element does not contain an entry expanding to @value, and element does not consist of a single entry expanding to @id (where entries are IRI expanded, set active context to previous context from active context, as the scope of a term-scoped context does not apply when processing new node objects.

I'm completely lost as to what I'm supposed to do here. Do I even need to do anything, or is this a "what we're about to do" introduction for the next steps? The way I'm reading it, it would seem to require I do something before I move on to step 8.

I've looked at a few other implementations to try and get a sense of what's going on, but they seem different from the spec. Both pyld and jsonld.js take a bunch of additional inputs to expansion, like insideList, insideIndex and typeScopedContext which have gone unmentioned so far. jsonld.net seems a bit closer, but their step 7 in expand seems to align with what's currently step 13.

[gkellogg]

The step is about managing the active context when there is a previous context. The following clauses limit the applicability of this for value objects and node references. In this case, the active context is set to the previous context, because term-scoped contexts do not have affect after you've descended into the object associated with that term.