Dependencies/backwards compatibility in Hackage

[Neil Mitchell]

Hi

> With version numbers, it suffices that each author has a rule of
> incrementing at a certain level if compatibility is broken.  It need
> not be the same level for different packages (though that would be
> less confusing).  They might have two levels of compatibility: merely
> adding functions, types or classes will not break any clients that use
> explicit imports.

We can of course automate this with haddock --hoogle and diff quite
easily. It doesn't get it perfectly - if the author changes the
semantics or introduces a type alias it won't give the right result,
but it should get the answer most of the time.

Thanks

Neil