Debian library packaging? or, how to get a single deb to work for hugs/ghc/nhc?

[Sven Panne]

Martin Sjögren wrote:
 > I have no idea how backwards compatible ghc is with respect to
 > libraries. If the ABI changes a lot between releases, that's a problem,
 > but if it's moderately predictable we can have dependencies on the form
 >   ghc5 (>= X.Y), ghc5 (<< X.Y+1)
 > I don't see why that won't work. [...]

In a nutshell: It doesn't work, even if only the patchlevel of GHC
changes and the user-visible ABI stays the same.  As has been discussed
several times, this is the price one has to pay for the heavy
inter-module optimizations GHC does. And recompilation is not always an
option, either, e.g. when the package in question has some native parts
which rely on development stuff (headers, program generators, etc.) which
is normally not installed on the target.

So we're basically left with two kinds of packages, IMHO:

    * Pre-compiled ones, tied to a particular compiler release

    * Source packages for "real" developers, not just Haskell users

Cheers,
    S.