import resolution (was RE: exposed packages and cabal depends)

[Simon Marlow]

Think of it like this: a collection of Haskell source files often share
common dependencies.  Those dependencies include packages, but also
things like what C libraries and header files are required by the code,
and what extra GHC flags might be required to compile it.  We find it
convenient to put all this information in one place: the .cabal file.

You can think of .cabal as part of the source if that helps.  It really
is part of the source - but implemented and specified as a layer on top
of existing language and compiler technology, for convenience and so
that we can share the tools.

When all the dependencies are explicit, the code is portable.  That's
what you're arguing for - but we're already there.  All you have to do
is write a .cabal file, cut-and-paste a 3-line Setup.lhs file, and
you're done.

And for free, we'll throw in a multi-compiler, multi-platform build
system and automated installation.  But that's not all!  Get Cabal, and
later we'll also give you automated dependency download and
installation, automated binary package generation in a variety of
formats, automated publishing and lots more.

Cheers,
	Simon