Haskell Platform proposal: Add the vector package

Roman Leshchinskiy rl at cse.unsw.edu.au
Tue Jun 19 00:06:56 CEST 2012

On 18/06/2012, at 19:39, Johan Tibell wrote:

> On Mon, Jun 18, 2012 at 9:54 AM, Bas van Dijk <v.dijk.bas at gmail.com> wrote:
>> I like the idea of the vector-safe package. Are you also proposing to
>> add this package to the HP? (I would also be +1 on that)
> I think it makes sense as a separate package, but I don't think it
> makes sense to add to the HP. SafeHaskell isn't used enough to warrant
> that.

I fully agree with Johan and I wouldn't even really want to maintain this separate package. It is a lot of work for something I don't use and don't entirely understand. The *.Safe modules in vector are currently bitrotted since I forget to update them when I add new operations and I'm not really sure what is and isn't "safe" anyway. Is anybody interested in this code at all?

>> I see that the trustworthiness of the .Safe modules is conditional on
>> whether bound checking is enabled in vector:
>> #if defined(VECTOR_BOUNDS_CHECKS)
>> {-# LANGUAGE Trustworthy #-}
>> #endif
>> The VECTOR_BOUNDS_CHECKS pragma would not be directly available in
>> vector-safe. But I guess, by using the install-includes cabal field,
>> vector can export a header file that exports this symbol when bound
>> checking is enabled.
> That sounds like a reasonable solution.

VECTOR_BOUNDS_CHECKS is defined in vector.cabal as follows:

  if flag(BoundsChecks)
    cpp-options: -DVECTOR_BOUNDS_CHECKS

Doesn't Cabal provide access to the flags that a package has been compiled with? It seems like it should and depending on the BoundsChecks flag would be cleaner than depending on a CPP symbol. 


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