[Nix-dev] GHC 7.8 plans

[Gergely Risko]

On Sun, 30 Mar 2014 16:16:24 +0200, Peter Simons <simons at cryp.to> writes:

> Does that sound like a reasonable plan?

Yes, thanks.

This is what I wanted to know, that you want to switch after packages
are OK and we're not waiting for a new haskell platform or whatever.
I'd prefer this way too, switch as soon as it works reasonably for
everything.

One more question regarding happy and alex.

In the current nixpkgs with ghc763, the default is happy 1.18 and alex
3.0 in the sense that e.g. the pandoc derivation uses these older
versions (through haskell-defaults.nix, I guess).  This is a bit
unfortunate for me, because on the other hand modern GHC (head and 7.8)
requires 1.19 and 3.1 to build.

May I ask why nixpkgs still prefers to build tools like pandoc with the
older happy?  Will pandoc not build with the newer 1.19 one, or is this
because 1.18 is specified in the current haskell platform?  Will this
change with 7.8?

I guess I could override happy used by pandoc with some nix expression
hacking, but then I lose the binary cache, so I don't want to do that
either.

Thanks,
Gergely