[Haskell-cafe] ANNOUNCE: vector-bytestring-

Stephen Tetley stephen.tetley at gmail.com
Sun Oct 16 08:51:54 CEST 2011

On 15 October 2011 23:56, Bas van Dijk <v.dijk.bas at gmail.com> wrote:
> On 15 October 2011 23:17, Ertugrul Soeylemez <es at ertes.de> wrote:
>> Both instances are valid here, and there is no mechanism to choose one of them.
> There is: OverlappingInstances[1] chooses the most specific instance.
> So in case someVector :: Vector Word8 the instance Show (Vector Word8)
> is chosen because it's the most specific.

This has the problem of incoherence in multi-module programs - GHC
might chose different instances for the same type depending on
compilation order. For a Show instance, this may be acceptable.

More information about the Haskell-Cafe mailing list