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On Mon, Aug 31, 2009 at 07:27:32PM +0100, Ciaran McCreesh wrote: |
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> Then when the user turns on all three: |
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> |
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> * If 'd' is enabled, if 'a' is enabled, 'b' must not be enabled |
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> * If 'd' is enabled, if 'a' is enabled, 'c' must not be enabled |
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> * If 'd' is enabled, if 'b' is enabled, 'a' must not be enabled |
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> * If 'd' is enabled, if 'b' is enabled, 'c' must not be enabled |
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> * If 'd' is enabled, if 'c' is enabled, 'a' must not be enabled |
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> * If 'd' is enabled, if 'c' is enabled, 'b' must not be enabled |
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> |
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> And in the general case, there's no way of translating the latter into |
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> the former. |
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> |
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> Much easier for everyone if you just say what you mean rather than |
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> converting it into some convoluted (but theoretically equivalent) less |
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> expressive syntax. |
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|
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I suggest alternative syntax, less powerfull but more expressive: |
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groups of use-flags. |
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|
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Guess we define the following flags in IUSE: |
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3d.nvidia 3d.ati 3d.intel |
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or |
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3d+nvidia 3d+ati 3d+intel |
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or |
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3d:nvidia 3d:ati 3d:intel |
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|
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In first case we may enable any number of those flags. |
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In second case we must enable at least one of them. |
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In third case we must enable exactly one of them. |
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In all 3 cases, if (and only if) flag '3d' itself exist in IUSE, |
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those flags are ignored when it is unset. |
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|
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For convenience, user may use '.' as middle-character in config in |
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all 3 cases (or, perhaps, even omit it and everything before it), |
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but in output of PM he will see proper character and understand |
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dependencies between flags without any explanation in English. |
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|
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If we add flag which depends on nvidia (e.g. cg), we name it |
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3d.nvidia.cg, and it will be ignored (perhaps with warning) if flag |
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3d.nvidia is unset. |
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