Multi-library/package support for cabal

Thomas Tuegel ttuegel at
Fri Jun 19 18:59:06 UTC 2015

On Fri, Jun 19, 2015 at 1:14 PM, Bardur Arantsson <spam at> wrote:
> Hi all,
> Given that I'm often quite annoyed by the almost-total lack of support
> for developing a set of coherent libraries together in a convenient
> fashion[1] using Cabal, I'd like to ask
> a) are there any current plans or GitHub issues on implementing any
> support for this workflow that I should be aware of?

There are two that I am aware of. [1] is very similar to one of your
workflows. [2] is related, but centers around improving the
interaction between sandboxes and multiple packages, and less on the
actual workflow of managing multiple packages simultaneously.


> c) would there be *interest* in somebody (e.g. me) implementing support
> for such a workflow?

Yes, definitely!

> d) if "yes" to c), how should one go about it? What kind of consensus
> needs to gathered and whom do I need to convince of the brilliance of
> this idea?

If what you have in mind is like #1367, I would say that consensus has
already been reached.

> I have a week's vacation coming up next week (and probably a few more a
> little later in the summer), and I think I may be able to dedicate quite
> a bit of time to getting this done, *but*... if I'm going to spend that
> time, I want something that can be integrated into cabal-install *and* I
> want something that has a reasonable chance of actually getting merged.
> (Of course, I don't expect bad code to be merged, but I'm quite happy to
> fix bad code whenever it's pointed out to me.)

I think there is some overlap with #2631, so I would suggest chiming
in there to avoid duplicating efforts. This is a frequently requested
feature; I think the chances of anything you write *not* being merged
are very, very small.

Thomas Tuegel

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