collections in hierarchical libraries

Simon Marlow simonmar at
Wed Jan 14 09:54:30 EST 2004

> No one seems to support Edison. However, there is an important
> difference between Edison and DData: DData provides implementations
> of specific structures, while Edison tried to provide general 
> collection
> interfaces *and* implementations. I believe that designing 
> good generic
> collection interfaces is very hard and may even be impossible 
> to do "right"
> in current Haskell's. So, I guess we will be stuck with concrete
> data structures for a while :-)

I second Daan's opinion here.  The Haskell community has been searching
for good generic collection interfaces for a while and hasn't come up
with anything that is obviously the right thing.  In the meantime we're
stuck with poor data structure support because everyone is waiting for
the wonderful generic collection library to come along.

Having a well-designed and consistent concrete data structure library is
certainly a lot better than nothing.  Indeed, it would be more useful in
a sense because the barrier to adoption would be low, and it wouldn't
have an impact on the existing libraries.  If such a thing were to
materialise, I'm sure we'd import it into the hierarchical libraries
that are shipped with GHC, Hugs & nhc98.

Perhaps DData is pretty close to what we're after.   Would the
interested parties care to thrash out the details and present it to the
wider community for comments?


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