Re: [Haskell-cafe] blaze-builder and FlexibleInstances in code that aims to become part of the Haskell platform

2011/5/20 Bas van Dijk :

On 19 May 2011 10:53, Johan Tibell wrote:

...

Long term we'd like to switch bytestring over from ForeignPtr to ByteArray#, if possible. There are currently some technical obstacles to such a switch

BTW I'm working with Roman Leshchinskiy to create the vector-bytestring package which provides: type ByteString = Data.Vector.Storable.Vector Word8 and exports the same API as the bytestring package (no support for lazy bytestrings yet)

A storable vector still uses a ForeignPtr but maybe this will make the switch to unboxed Vectors (which use ByteArray#) easier.

Expect some code to be up somewhere next week.

Bas

OK, that sounds interesting. I'm looking forward to your code. One trick, I'm using in the blaze-builder implementation is that the current buffer is denoted by a region (pf :: Ptr Word8, pe :: Ptr Word8) of the next free byte `pf` and the first byte after the buffer `pe`. This only works for pinned ByteArrays/ForeignPtrs. Do you know what the cost of such an array/foreignptr is? Moreover, after creation I could "unpin" the array. Do you perhaps know if thats possible in principle? best regards, Simon