[Haskell-cafe] portable arrow instances

[Wolfgang Jeltsch]

Hello,

how do I make a library work with both GHC 6.8 and GHC 6.10?  According to 
<http://www.haskell.org/haskellwiki/Upgrading_packages#Arrow_instances>, I 
should change all my Arrow instances but then they don’t work with GHC 6.8 
anymore, do they?  Or is the solution to force GHC 6.8 users to use 
base-4.0.0.0?

Best wishes,
Wolfgang