On Sat, Jan 12, 2013 at 8:07 AM, Herbert Valerio Riedel <hvr@gnu.org> wrote:

| Every package should fulfil the following requirements. Any
| requirements that are not met must be clearly explained and justified
| in the proposal.
|
| [...]
|
| - Compile on all operating systems and compilers that the platform
| targets. [rationale-8.4]

But I couldn't find any explictly stated list which compilers beyond GHC
(and which version(s) of GHC?) the HP actually wants to target.

As of right now, there is exactly one production-quality Haskell implementation, which is the only one the platform targets, so by definition a library using GHC-specific features is appropriate for inclusion in the platform. An argument can be made to change the definition, but that's what it is right now.

A especially strong -1 from me to any effort to enforce Haskell 98 compatibility for Haskell Platform packages: that standard is 15 years old now, and has been superseded by Haskell 2010. At this point I think the argument for standards breaks down altogether because there's only one conformant Haskell 2010 implementation. It's not GHC's fault it doesn't have viable competitors: we shouldn't be making busy-work for package authors to make their code portable to other Haskell implementations that don't exist yet.

--
Gregory Collins <greg@gregorycollins.net>