Make it compile with MicroHs

[augustss]

Two changes

• MicroCabal cannot parse everything cabal can
• MicroHs always has MonoLocalBinds, so some type signatures are required.

[phadej]

I actually dropped the support for pre GHC-8.0, so this conditional's else-branch can be removed. Do you mind?

I'm not sure whether Hackage is using new enough Cabal to accept impl(mhs) .

[augustss]

You can remove the else branch if you want.

Cabal accepts mhs as a valid compiler now, I believe.

[augustss]

Hmm. Maybe the CI is using some older cabal?

[phadej]

Cabal accepts mhs as a valid compiler now, I believe.

newer Cabal does. But hackage-server still uses old Cabal, so this change could not be released. (And it might take quite a long time).

[Bodigrim]

At the moment Hackage uses Cabal 3.12.1.0, which knows about MHS:

• https://hackage.haskell.org/package/Cabal-syntax-3.12.1.0/docs/Distribution-Compiler.html#t:CompilerFlavor
• https://github.com/haskell/cabal/blob/master/release-notes/Cabal-3.12.1.0.md

[phadej]

@Bodigrim good to know. But given a thought, if the thing can be written without impl(mhs), it should.

You help me, I help you. I'm sorry, but I don't care about MicroHS, so if I can be unaware I will.

That said, the first moment the CI breaks, I will remove it; so adding CI for microhs is somewhat unnecessary too. I won't put any effort into it.

TL;DR my stance is: GHC is the only compiler out there. The ship for multi-compiler ecosystem has long sailed away.

[augustss]

If there is no support for pre-8.0 GHC then the condition can be simplified and it will work with MicroHs.

[phadej]

I started this discussion with saying

I actually dropped the support for pre GHC-8.0, so this conditional's else-branch can be removed. Do you mind?

---

This left a bad taste. I removed the conditional, so AFAICT this patch has only MonoLocalBinds changes which are relevant.

[phadej]

For a time being, I won't accept changes using impl(mhs).

[phadej]

... but I don't really care anymore. I see there are a forks of transformers and mtl, so I guess you will have to maintain a fork of parsec too.

[augustss]

The MicroHs changes to transformers have been accepted a long time ago. But since the master copy of the source is in darcs I have a copy in my GitHub repo.
I've not submitted a PR for mtl yet, but I will soon.
I only keep a (divergent) fork until the changes have been accepted. It's worked smoothly with other packages like containers and time.

[augustss]

Ah, I miunderstood you comment about dropping support for 8.0. I thought you'd done it, but not yet changed the parsec.cabal file, but it was just that I hadn't synced my repo. My bad.
Thanks for the change, that's excellent!