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On Thu, 22 Feb 2007 22:02:27 +0100 Simon Stelling <blubb@g.o> |
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wrote: |
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| Ciaran McCreesh wrote: |
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| > || ( |
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| > sdl? ( media-libs/libsdl ) |
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| > svga? ( media-libs/svgalib ) |
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| > opengl? ( virtual/opengl ) |
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| > ggi? ( media-libs/libggi ) |
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| > virtual/x |
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| > ) |
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| |
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| It's doable with just use. For the example above, this would be the |
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| solution: |
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| |
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| interface="x11" |
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| use ggi && interface="ggi" |
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| use opengl && interface="opengl" |
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| use svgalib && interface="svga" |
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| use sdl && interface="libsdl" |
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|
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I'll explain why this doesn't work for the benefit of anyone who misses |
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it... |
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|
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Consider the user having USE="sdl svgalib", and already having svgalib |
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installed. Then sdl will not be pulled in, and the above solution will |
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give the wrong interface. |
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|
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| > So, is there a legitimate reason for this complication to exist? Or |
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| > should use? blocks being direct children of || ( ) be forbidden? |
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| |
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| I don't see how this is a complication, tbh. The alternative would be |
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| to have the same DEPEND but without the ||(). But then you would have |
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| to a) let the ebuild die if more then one flag is turned on or b) |
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| have it follow the same logic as shown above. |
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| |
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| I also don't see how it is a nuisance to explain. Explain how ||() |
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| works with a "normal" dependency, explain how use? () dependencies |
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| work and it will become clear to everybody how it will work. TBH, it |
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| looks to me like you were to explain how an if statement in a while |
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| loop works, even though it is well-known how both of them work if |
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| they aren't nested. |
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|
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Except that that's not what happens. The current behaviour makes if |
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work differently if it's a direct child of a while loop. The following |
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are not equivalent: |
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|
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|| ( foo? ( bar/foo ) bar/baz ) |
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|
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|| ( ( foo? ( bar/foo ) ) bar/baz ) |
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|
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The former will always require either foo or baz, whereas the latter |
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will sometimes require neither. |
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|
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-- |
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Ciaran McCreesh |
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Mail : ciaranm at ciaranm.org |
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Web : http://ciaranm.org/ |
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Paludis, the secure package manager : http://paludis.pioto.org/ |
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