where's Control.Applicative.Compat

[simonmichael]

0.8.0 dropped Control.Applicative.Compat. Where can this be found now ? (simonmichael/hledger#245)

[sol]

The orphan instances are in base-orphans now.

Data types in general we dropped for now, as some of the data types that were added to base are already provided by other packages. Here is my stand on this #17 (comment). But I appreciated feedback.

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On 22 Apr 2015, at 11:07 pm, Simon Michael notifications@github.com wrote:

0.8.0 dropped Control.Applicative.Compat. Where can this be found now ?

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[RyanGlScott]

Now that I think about it, I think we forgot to update the changelog to reflect this. It might not hurt to make a 0.8.0.1 release with CHANGES.markdown added to the extra-source-files section of the .cabal file to reduce confusion in the future.

[sol]

Damn! Yes, I missed that. What do you think about linking to the changelog on github instead, for proper markdown formatting?

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On 22 Apr 2015, at 11:40 pm, Ryan Scott notifications@github.com wrote:

Now that I think about it, I think we forgot to update the changelog to reflect this. It might not hurt to make a 0.8.0.1 release with CHANGES.markdown added to the extra-source-files section of the .cabal file to reduce confusion in the future.

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[RyanGlScott]

We could do both. I like having the changelog section of the Hackage page link to something, since that's where I usually look first to get an idea of what changed.

[sol]

Ok, cool, works for me. It's already late here, but I can update the changelog tomorrow, unless you want to take care of it.

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On 23 Apr 2015, at 12:05 am, Ryan Scott notifications@github.com wrote:

We could do both. I like having the changelog section of the Hackage page link to something, since that's where I usually look first to get an idea of what changed.

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[simonmichael]

I was using eg (<*) from Control.Applicative.Compat, which I don't think is in base-orphans ?

[RyanGlScott]

Ah. In that case, I think you are using Control.Applicative.Compat in a way we weren't quite intending. The purpose of base-compat is to provide a retrofitted version of base that exports functions whose implementations and type signatures match the most recent version of base, without requiring end users to use CPP pragmas to import it. As a result, we only export a .Compat module if there has been changes to functions in that module between versions of base.

In the case of Control.Applicative, nothing inside of the module (related to functions, at least) was changed in base-4.8.0.0, but rather, the Applicative typeclass was reexported from Prelude. Instead of doing something like this:

#if !MIN_VERSION_base(4,8,0)
import Control.Applicative.Compat ((<*))
#endif

why not do this:

import Prelude ()
import Prelude.Compat

You get the same functionality with no CPP pragmas.

[sol]

No, but it's in Control.Applicative for all supported versions of base. Control.Applicative.Compat did not define any functions nor operators. https://github.com/haskell-compat/base-compat/pull/21/files#diff-22b439017b3fdc587c4fd621f6c56078L1

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On 23 Apr 2015, at 12:37 am, Simon Michael notifications@github.com wrote:

I was using eg (<*) from Control.Applicative.Compat, which I don't think is in base-orphans ?

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[sol]

why not do this:

import Prelude ()
import Prelude.Compat
Yes, ignore my previous mail. This is what you want.

(Ryan, I edited your code in the quote and removed the import list for Prelude.Compat. That's what you meant, right?)

[simonmichael]

Yes, I was trying to keep things building before and after GHC 7.10. Clearly it's not as simple as "just use base-compat". Thanks for the hints.

[RyanGlScott]

We definitely didn't advertise this change as well as we should have, given how substantial it was. (I uploaded base-compat-0.8.0.1 with the changelog highlighted just in case.)

I'll go ahead and close this for now–please let us know if there are other issues in using base-compat-0.8.

[simonmichael]

All clear now, thank you.