DData modules

Jan-Willem Maessen jmaessen at alum.mit.edu
Thu Jan 13 08:31:51 EST 2005

On Jan 13, 2005, at 7:38 AM, Ross Paterson wrote:

> On Thu, Jan 13, 2005 at 02:37:39AM -0800, Simon Marlow wrote:
>> simonmar    2005/01/13 02:37:39 PST
>>   Modified files:
>>     libraries/base       package.conf.in
>>     libraries/base/Data  FiniteMap.hs Set.hs
>>   Added files:
>>     libraries/base/Data  IntMap.hs IntSet.hs Map.hs
>>   Log:
>>   Add Data.Map, Data.Set, Data.IntMap and Data.IntSet from Daan 
>> Leijen's
>>   DData library, with some modifications by JP Bernardy and others on
>>   the libraries at haskell.org list.  Minor changes by me to remove the
>>   last references to DData, and add a DEPRECATED copy of the old
>>   Data.Set interface to the new Data.Set.
> Int{Map,Set} use the type Word, but I think it was decided a while ago
> that this type shouldn't be standard.  Should that be reconsidered?

Please.  I've had untold frustration in the past trying to 
impedence-match different implementations of fixed-width unsigned 
binary arithmetic.

> Also, these modules import Data.Monoid, which contains the non-H98 
> instance
> Monoid (a -> a), making it (and these) non-portable.  One way out 
> would be
> to replace that instance in Data.Monoid with one for
> data Endo a = Endo { runEndo :: a -> a }

This is a huge frustration for the library writer: define the instance, 
and give up portability, or leave it out, and eliminate some obvious 

-Jan-Willem Maessen

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