On Friday 23 February 2007, Kevin F. Quinn wrote:
> On Thu, 22 Feb 2007 19:08:48 +0000
>
> Ciaran McCreesh <[EMAIL PROTECTED]> wrote:
> > The example given in ebuild(5) is:
> > || (
> >
> > sdl? ( media-libs/libsdl )
> > svga? ( media-libs/svgalib )
> > opengl? ( virtual/opengl )
> > ggi? ( media-libs/libggi )
> > virtual/x
> > )
>
> Took me a while to figure out why anyone would want to write that; the
> key is that ebuild(5) says only one of the conditions is satisfied;
> i.e. even if all the dependencies are present on the system, the
> package will build only against the first matching dependency.
>
> The way I see it, the ebuild has to cater for the dynamic situation
> anyway, for example doing something like:
>
> src_configure() {
> use sdl &&
> has_version media-libs/libsdl &&
> vid_conf="--enable sdl" ||
> use svga &&
> has_version media-libs/svgalib &&
> vid_conf="--enable svga" ||
> use opengl &&
> has_version virtual/opengl &&
> vid_conf="--enable opengl" ||
> use ggi &&
> has_version media-libs/libggi &&
> vid_conf="--enable ggi" ||
> vid_conf="--enable x11"
> ...
> econf ${vid_conf} ...
> }
>
> So the dependency could be re-written as:
>
> sdl? ( media-libs/libsdl )
> !sdl? ( svga? ( media-libs/svgalib )
> !svga? ( opengl? ( virtual/opengl )
> !opengl? ( ggi? ( media-libs/libggi )
> !ggi? ( virtual/x ) ) ) )
>
> and you have the same result, which means the originally quoted syntax
> is redundant. The only advantage it has is that it looks a little bit
> prettier - but I'd argue the logic is clearer in the re-written version.
>
> I guess the question remains, though - should that syntax be in EAPI=0
> or not...It is only really acceptable for buildtime only dependencies as after the build phase nothing is actually different. Paul -- Paul de Vrieze Gentoo Developer Mail: [EMAIL PROTECTED] Homepage: http://www.devrieze.net
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