[Haskell-cafe] instance Binary UTCTime (Was: Oprhan instances)

[Alexander Dunlap]

On Sun, Nov 29, 2009 at 5:37 AM, Duncan Coutts
<duncan.coutts at googlemail.com> wrote:
> On Thu, 2009-11-26 at 16:40 -0500, David Menendez wrote:
>
>> The problem with this solution is that it doesn't scale. If we have M
>> packages providing types and N packages providing classes, then we
>> need M*N additional packages for orphans.
>>
>> The best long-term solution is probably extending Cabal to handle this
>> more transparently, perhaps by allowing packages to depend on flagged
>> versions of other packages (e.g., foomonad >= 4.0 && < 4.1 && HAS_MTL)
>
> Not going to happen. Such packages could not be translated into binary
> distro packages.
>
> Duncan
>

Wouldn't the distro just choose one set of flags for each package and
then other packages would either be satisfied or not satisfied based
on which flags had been chosen? It seems to me that distros could even
offer multiple options for the same package with different flags set.
What wouldn't work?

Alex