On Mon, 2012-05-07 at 11:11 -0700, Zac Medico wrote:
> On 05/06/2012 05:47 PM, Arfrever Frehtes Taifersar Arahesis wrote:
> > 2012-05-06 02:34:26 hasufell napisał(a):
> >> # grep :webkit use.local.desc | wc -l
> >> 33
> >>
> >> I would vote to make this a global useflag:
> >>
> >> webkit - Adds support for the webkit library/module
> > 
> > I suggest to use separate qt-webkit (or webkit-qt) and webkit-gtk USE flags.
> 
> Another possible way to model this kind of relationship would be to us
> REQUIRED_USE to enforce relationships with the qt and gtk flags:
> 
> REQUIRED_USE="webkit? ( qt ) !webkit? ( !qt ) qt? ( webkit ) !qt? (
> !webkit )"
> 
> versus
> 
> REQUIRED_USE="webkit? ( gtk ) !webkit? ( !gtk ) gtk? ( webkit ) !gtk? (
> !webkit )"
> 
> It's pretty awkward with the existing operators, but we could extend the
> REQUIRED_USE syntax to support an equivalent operator in a future EAPI.

Isn't it the time to make a new EAPI which no longer has USE "flags" but
USE "values" ? Many of the really weird USE flags combinations would be
much more clearly expressed if the possible types for a USE variable
were:
1) member-of: for choosing the backend of certain functionality; e.g.
all combinations of USE="ssl openssl gnutls nss" would become e.g.
in the ebuild:
USE="ssl=[member-of: openssl,gnutls,nss]"
in make-conf:
USE: ssl=openssl, as synonymous of old USE="ssl openssl", or
USE: ssl=none, as synonymous of old USE="-ssl"
2) subset-of: for selecting a number of modules to build. This would
replace USE_EXPAND quite neatly
3) boolean: as alias for member-of: [true,false]
4) unsigned int: IIRC some (few) packages can take optional uint at
configure-time. for example with dev-lisp/sbcl one can customize some
hardcoded GC parameters suchs as the default heap size, generation size,
etc...

In the above case, one could have a USE variable named "webkit" of type
member-of: [qt,gtk]

-- 
Stelian Ionescu a.k.a. fe[nl]ix
Quidquid latine dictum sit, altum videtur.
http://common-lisp.net/project/iolib