[Haskell] Re: Trying to install binary-0.4
nominolo at googlemail.com
Sun Oct 28 14:08:30 EDT 2007
On Sun, 2007-10-28 at 13:49 -0400, Isaac Dupree wrote:
> Simon Marlow wrote:
> > Probably it could be made clearer. In 4.2 the idea is that instead of
> > replacing
> > base-2.0 ==> base-3.0 + directory-1.0 + array-1.0 + ...
> > you would replace
> > base-2.0 ==> newbase-1.0 + directory-1.0 + array-1.0 + ...
> > and additionally have a package base-3.0 that re-exports the whole of
> > (newbase + directory + array + ...).
> "Macros" in cabal: Why not just say that depending on base-3.0 actually
> means that you have to depend on newbase-1.0, and directory-1.0, etc...
> Why is compiler support needed? is it really possible that I still
> don't understand?
You'd still have the problem that every package has to specify this
"macro" for itself. You'd want some global macro-database to avoid
this. The better solution would be to just have a package that
re-exports everything. I.e., the definition of package base-2.0 would
look something like this:
if has system has base-3.0, directory, array ...
exposed-modules: Data.Maybe, Data.List, ...
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