Splitting SYB from the base package in GHC 6.10

Ross Paterson ross at soi.city.ac.uk
Wed Sep 3 04:13:56 EDT 2008

On Wed, Sep 03, 2008 at 12:29:09AM +0100, Claus Reinke wrote:
> If I understand José's intentions correctly, the idea is to keep the
> 'Data' class intact this round, but to give the 'syb' package maintainer
> and users the flexibility to try and improve the situation with 'Data'
> instances; ie, either
>    - improve the currently partial and incomplete instances, or
>    - not provide/import those instances that can't be completed
> But if the existing incomplete instances are not moved out of
> the way, their implicit import/export will always interfere with
> whatever new instances 'syb' might try to provide.

I think the area of contention is pretty small.  As I understand it,
no-one wants to change the instances you call [standard], for the types

	[] Maybe Either tuples
	() Bool Ordering Char Double Float Handle 
	Integer Int Int8 Int16 Int32 Int64 Word Word8 Word16 Word32 Word64
	DataType TyCon TypeRep

So they might as well go with the Data class.  That leaves the [partial]
instances that would have to be taken out of syb to make most of the
other packages independent of it:

	Ratio Complex
	Ptr StablePtr ForeignPtr

Assuming something sensible is done for the first two, would there really
be any need to change these?

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