xget should work on set compositions

[ithayer]

instead of having to declare the entire set names, it would be nice if it used the composition functions, eg: the "intersections" forms

[bwo]

Not sure where this would go in xget itself. There's are already intersection-name and union-name functions (complement-name would be worth adding) for generating the names of derived sets from the names of input sets.

Xget could also just return the results across all sets, but as long as you want to be able to specify only some sets, it seems like an issue about getting set names rather than directly about xget.

[bwo]

closed by 2e2183d