Proposal: register a package as providing several API versions

Ketil Malde ketil+haskell at
Tue Oct 16 10:37:21 EDT 2007

ChrisK <haskell at> writes:

> Once it is possible to have cabal register the hsFoo-3.0.0 also as hsFoo-2 it
> will be easy to upgrade to hsFoo.  No old programs will fail to compile.

> Who here knows enough about the ghc-pkg database to say how easy or hard this
> would be?

Ignoring disk space, I suppose the motivation is that it will ease the
user experience by only having to download, compile and install a
single package?  And perhaps ease the maintenance a bit for the
library author, too.

One way to do this would be to have multiple .cabal files in the
package, with small differences like different version numbering.
You can use a Makefile or other hack to automate switching.

If I haven't seen further, it is by standing in the footprints of giants

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