GHC on Windows (extended/broad discussion)

Austin Seipp austin at
Sat Oct 25 00:24:23 UTC 2014

Gintautas, Tamar, Roman,

(CC'ing those on, and Kyrill,
who has helped us out much in the past)

Thank you all for all your help with Windows recently. I apologize for
not responding to some of your concerns sooner in the recent threads
about tarballs, etc.

First off, all your contributions are extremely welcome - GHC has had
many talented Windows hackers in days long past, but these days this
number has dwindled! Anyone who has an interest in GHC on Windows is
in a place to make a big impact and help us. All the work Gintautas
has done for example, will dramatically improve the ghc-tarballs

On that note: Gintautas, I will get D339 merged in ASAP, as soon as I
test it and make a download mirror for you. has an awesome
new CDN setup, and once I implement, it
will be easy to update tarballs and serve them to mass amounts of

However, beyond that, we still need more done. First off, if you can
help, we can help you! We can make lots of Windows build bots for
people on demand, so if you're in desperate need of disk space or your
computers are a bit slow, we can help accommodate.

Right now, we have nightly builds with Gabor's[1] build system, and
soon, we're working on a Phabricator integration, which should be
great - and hopefully reduce the amount of breakage substantially.

I also notice there is a ticket list of Windows issues[2], and that's
fantastic. After a quick glance, a lot of these tickets are old,
duplicates, or could possibly be closed or fixed easily. A good first
task for any new contributor would be to go through this list, and try
to replicate some of them! And you can always ask me - I can certainly
help you navigate GHC a bit to get somewhere.

But there are still other things. The Win32 package for example, is
dreadfully lacking in maintainership. While we merge patches, it would
be great to see a Windows developer spearhead and clean it up - we
could even make some improvements in GHC itself based on this. This
would be an excellent opportunity to make a good impact in the broader

Finally, we desperately need someone to consult with when we're up a
creek. Are certain patches OK for Windows? What's the best way to fix
certain bugs, or implement certain features? I feel like often we try
to think about this, but it's a bit lonely when nobody else is there
to help! I'm not sure how to fix this, other than encouraging things
like doing active code reviews and helping grind out some patches. But
at the very minimum, I'd just like to talk with you about things

So in summary - the work so far is grand, and we want to help you do
more! And I'm sure everyone can help - there's always so much to do
and so little time, we need to encourage it all we can.

As Simon says: Upward and Onward!



Austin Seipp, Haskell Consultant
Well-Typed LLP,

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