Using GHC.TypeLits and singletons

Richard Eisenberg eir at
Mon Oct 29 16:50:08 CET 2012

You do recall correctly; they are supposed to work together. We discovered that they didn't a few weeks ago. Iavor has updated his implementation of TypeLits in HEAD. I still have to update singletons, which I will now do. Expect this update later today. In the meantime, make sure you have a version of libraries/base pulled in the last 13 days, as you will need the updated TypeLits.


On Oct 29, 2012, at 5:46 AM, José Pedro Magalhães <jpm at> wrote:

> Hi Iavor and Richard (CC ghc-users),
> If I recall correctly, Richard designed his singletons package in such a way that it would interact nicely
> with Iavor's type-level literals. Now I find myself in a situation where I need to use both type-level literals
> and singletons (basically because I'm reflecting at the value level both naturals, strings, and more
> complicated datatypes). But I see that the declarations of entities such as Sing, SingI, etc., are 
> duplicated in the singletons package (seeing that they are already in GHC 7.6 within GHC.TypeLits).
> My question is: how can I use these two together?
> Thanks,
> Pedro

More information about the Glasgow-haskell-users mailing list