hello, irrespective of if DData is "the" data structure library (whatever that means), or simply another library, could we avoid adding it to the base package? it would be much nicer, if the base package was split into more components.

and it would also be nice if i can go and download DData on its own, whenever there are bugfixes, or improvements, without needing to download GHC with it. i don't see any reason why DData should be part of "base".

A rough criteria for what should be in 'base' is: everything required by Prelude. I say only a rough criteria, because there are currently plenty of libraries in base that aren't required by the Prelude, but are there because splitting them off into a separate package would be overkill. (Also at one stage I was using a different criteria: everything required to bootstrap GHC). Cheers, Simon