[Haskell-cafe] Please check your dependencies on fgl

Don Stewart dons at galois.com
Mon Jun 7 18:32:55 EDT 2010

> Oh, great, the email _did_ go out on the mailing lists (what with
> haskell.org being down I wasn't sure it would).
> Don Stewart <dons at galois.com> writes:
> > ivan.miljenovic:
> >> Thomas Bereknyei are currently re-writing fgl (just about completely
> >> from scratch) and we plan to make an initial release to get feedback
> >> on the API in the next few weeks.
> >> 
> >> However, I'm sending this email out now to warn people that I highly
> >> doubt any code that was written for the current version of fgl
> >> (http://hackage.haskell.org/package/fgl- will work with the
> >> new version.
> >
> > How about you give the library a different name then -- so as not to
> > break all those programs?
> >
> > A complete rewrite with a new maintainer: fgl-awesome
> We considered giving it a new name (fgl', etc.) but figured that in the
> long term this wouldn't be advantagous.  We feel that the situation is
> analogous to QuickCheck: when the new version came out most people kept
> using the old one until slowly the momentum shifted and more people
> started using the new version (without checking in depth, Roel's Hackage
> mirror reports QC-2.x now has 153 reverse dependencies as opposed to 127
> reverse dependencies for QC-1.y).

Just remember: you are now the maintainer of a package in the Haskell
Platform, and that has some burden on ensuring stability and safety.
API-breaking changes are fine, as long as well planned, and it may be up
to 12 months before the HP can adopt an API changing release of a

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