>>>>> On Mon, 29 May 2017, Michał Górny wrote:

> On pon, 2017-05-29 at 20:00 +0200, Alexis Ballier wrote:
>> Can you provide an efficient algorithm for the above syntax? That
>> is, given a set of +/- useflags forced by user, output the set of
>> effective useflags (or a rant if it is inconsistent).

> I'd rather leave that to people who are good with algorithms. I find
> the whole thing scary but I don't really see a sane alternative here.
> Worst case, we have to figure out some arbitrary limitations to keep
> things sane.

IMHO the sanest alternative would be to restrict the syntax to USE
conditional forms which have an obvious solution. One of the many
problems of REQUIRED_USE is that it sometimes requires solving a
Zebra Puzzle.

Also, can we find a better name? Sorry for the bikeshedding at this
early stage, but I believe that ENFORCED_USE can be easily confused
with use.force in profiles. MAPPED_USE? USE_MAP?

Ulrich