I'd like to ask for a new Search Language Modifier: ~expand=fields
This would function identically to the current ~a modifier, which expands the current selection to include all tracks from each album, except that you could choose which field to expand. So, for example, the current ~a modifier would be equivalent to ~expand=[Album], but you could also do ~expand=[Series] or ~expand=[Artist] to expand the selection to all files from the same [Series] or [Artist] respectively. Or, like ~limit, combinations thereof if desired.
I think, since you already have the ~a logic, it should be relatively simple to implement (I know, I know, I shouldn't guess about these things). The new feature would be incredibly powerful, though, and would solve many long-standing View and search construction problems I have, which lead you down a "we need iterators" rabbit hole.
For example, one thing I've wanted to build for a long time is a Shows We're Currently Watching view, for Theater View. This would automatically limit the results to:
* Any TV Show [Series] where [Last Played] of any episode of that series is within the last 8 weeks.
* All unwatched episodes of the resulting series
This is effectively impossible to do with the current capabilities of Media Center, because you'd need to iterate over [Last Played] for all episodes in a [Series] and then pick out a list of "Series items" (instead of just those individual files). But the ~expand modifier would make this a thing of the past. You could just make a "Currently Watching Series" Smartlist that does the Last Played math, and then expands to [Series]. Then, point your View at that Smartlist, and limit it to unwatched episodes.
I can think of all sorts of other uses. For example, I'd like to make a "Favorite Artists" music view as well. This would show not just individually favorited tracks, but all tracks by any artist that has at least one track with four or more stars.
You could use this any time you want to search your Library for "all files where other files by that same [Field] meet these conditions" kind of lookup. You can't do that in Media Center currently, and it is a fairly major limitation. This solution wouldn't meet all needs of this type completely cleanly (but using the "recursive smartlists" trick to re-filter, you really could do a lot with it), but I think it falls into the categories of:
* Using and expanding what we already have without requiring a major overhaul
* Solving a wide variety of use cases
So... What do you say? Is that something you could add?