[Haskell-cafe] ANN: primitive 0.6.4.0

Thu May 31 00:03:59 UTC 2018

Thanks for the feedback. Also, thanks for the giant PR you made a year ago. Several of the things I implemented in this release were just things I ripped out of it and put into smaller PRs. To address your questions:

- There are more combinators in PrimArray than there are in the other modules. This is an inconsistency in the library design. We need to come up with a policy for what combinators are accepted. It’s weird to have a Foldable instance for Array but not get access to foldl’ and foldr for PrimArray and UnliftedArray. Similarly, functions for mapping and travsersing seem reasonable just so that you have access to the same interface if you switch from using Array to one of the other array types that isn’t fully polymorphic in its element type. I’ve considered removing some of the functions (like replicatePrimArray) in a future release. The maintainers of primitive don’t all share the same view on what exactly should be there, so we probably need to come up with a policy around this.
- We should definitely have toList be a good producer. This has been discussed in other PRs. A PR for this would be accepted.
- The generalized MVar is basically useless without unsafely extending it (ie forkST). But, everything provided is 100% deterministic. You have to write forkST on your own and take on the burden of proving that you use it in a way that results in deterministic behavior. I have written a package that implements a parallel variant of mergesort that needs this kind of this. I think there’s something Carter wanted to do with this as well.

Sent from my iPhone

> On May 30, 2018, at 4:19 PM, Dr.Koster <drkoster at qq.com> wrote:
> 
> I have make some comments on reddit, but still I want to record them here:
> After reading the new code, I got a feeling that there're some API lacking considerations. Here is some of my personal concerns:
> The generalized MVar is basically useless because ST is meant to seal its state token, you won't want to add a forkST. You can argue that the atomic operations on MutVar is already added, but still I want to justify its usefulness.
> 
> There're too much combinators added to PrimArray, is there a plan to port these to other arrays? 
> 
> If we ever provide toList operations, then I would really want it to be a good producer in base's fold-build fusion' view, it's robust and easy to implement, and folding is basically the same speed with List.fold and toList.
> 
> Anyway it seems I missed the bike shedding, but still I want to thank for all the efforts, I'll try to follow new GitHub workflow more closely.
> 
> Cheers 
> Winter
> 发自我的iPhone
> 
> 
> ------------------ Original ------------------
> From: Carter Schonwald <carter.schonwald at gmail.com>
> Date: Thu,May 31,2018 2:55 AM
> To: haskell-cafe <haskell-cafe at haskell.org>, Haskell Libraries <libraries at haskell.org>
> Subject: Re: [Haskell-cafe] ANN: primitive 0.6.4.0
> 
> This is a pretty exciting (albeit minor version)
> 
> I'd like to especially thank David Feuer (treeowl ) and Andrew Martin (andrewthad) for their contributions
> 
> the change log has a huge number of bug fixes relative to 0.6.2-3
> 
> also we added some new modules of features 
> 
> PrimArray --- unboxed nonsliceable vectors
> MVar -- Mvars that run in any PrimMonad
> 
> augmented the Data.Primitive exports for increased consistency 
> (the new .Ptr and .Mvar modules aren't exported in this minor version so users can easily migrate)
> 
> Changes in version 0.6.4.0
> 
> Introduce Data.Primitive.PrimArray, which offers types and function for dealing with a ByteArray tagged with a phantom type variable for tracking the element type.
> 
> Implement isByteArrayPinned and isMutableByteArrayPinned.
> 
> Add Eq1, Ord1, Show1, and Read1 instances for Array and SmallArray.
> 
> Improve the test suite. This includes having property tests for typeclasses from base such as Eq, Ord, Functor, Applicative, Monad, IsList, Monoid, Foldable, and Traversable.
> 
> Fix the broken IsList instance for ByteArray. The old definition would allocate a byte array of the correct size and then leave the memory unitialized instead of writing the list elements to it.
> 
> Fix the broken Functor instance for Array. The old definition would allocate an array of the correct size with thunks for erroring installed at every index. It failed to replace these thunks with the result of the function applied to the elements of the argument array.
> 
> Fix the broken Applicative instances of Array and SmallArray. The old implementation of <*> for Arrayfailed to initialize some elements but correctly initialized others in the resulting Array. It is unclear what the old behavior of <*> was for SmallArray, but it was incorrect.
> 
> Fix the broken Monad instances for Array and SmallArray.
> 
> Fix the implementation of foldl1 in the Foldable instances for Array and SmallArray. In both cases, the old implementation simply returned the first element of the array and made no use of the other elements in the array.
> 
> Fix the implementation of mconcat in the Monoid instance for SmallArray.
> 
> Implement Data.Primitive.Ptr, implementations of Ptr functions that require a Prim constraint instead of a Storable constraint.
> 
> Add PrimUnlifted instances for TVar and MVar.
> 
> Use compareByteArrays# for the Eq and Ord instances of ByteArray when building with GHC 8.4 and newer.
> 
> Add Prim instances for lots of types in Foreign.C.Types and System.Posix.Types.
> 
> Reexport Data.Primitive.SmallArray and Data.Primitive.UnliftedArray from Data.Primitive.
> 
> Add fold functions and map function to Data.Primitive.UnliftedArray. Add typeclass instances for IsList, Ord, and Show.
> 
> Add defaultSetByteArray# and defaultSetOffAddr# to Data.Primitive.Types.
> 
> 
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