Can containers depend on Template Haskell?

[Mark Lentczner]

On Dec 4, 2010, at 3:07 AM, Henning Thielemann wrote:

> That's not possible - a package at a specific version must export the
> same API independent of the compiler, operating system and so on.

I agree that that is desirable, but I don't understand why it is a "must". I can easily imagine packages where, one or two extra functions are available depending on the arch, os, or compiler version. We currently have the functionality in cabal and GHC to have conditional compilation based on such factors. So, we should recognize that it is possible, and at times, a reasonable design compromise. Or at the very least, even if we believe it is a bad design choice, we should recognize that other library developers may think otherwise.

	- Mark