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On Tue, 30 May 2017 00:01:16 +0200 |
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Ulrich Mueller <ulm@g.o> wrote: |
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> >>>>> On Mon, 29 May 2017, Michał Górny wrote: |
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> > On pon, 2017-05-29 at 20:00 +0200, Alexis Ballier wrote: |
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> >> Can you provide an efficient algorithm for the above syntax? That |
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> >> is, given a set of +/- useflags forced by user, output the set of |
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> >> effective useflags (or a rant if it is inconsistent). |
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> |
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> > I'd rather leave that to people who are good with algorithms. I find |
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> > the whole thing scary but I don't really see a sane alternative |
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> > here. Worst case, we have to figure out some arbitrary limitations |
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> > to keep things sane. |
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> |
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> IMHO the sanest alternative would be to restrict the syntax to USE |
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> conditional forms which have an obvious solution. One of the many |
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> problems of REQUIRED_USE is that it sometimes requires solving a |
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> Zebra Puzzle. |
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Solving zebra puzzles isn't really that bad in practice most of the |
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time. The tricky bit is finding the *right* solution, given poor input |
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data that doesn't really let you evaluate what right is. As a simple |
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example, in the olden days, the most obvious and shortest answer to |
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fixing Gnome resolution errors was to set USE=mips because that |
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disabled a whole load of browser dependencies... |
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-- |
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Ciaran McCreesh |
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