Have a look at the Package Versioning Policy:
http://haskell.org/haskellwiki/Package_versioning_policy
On Sun, Oct 11, 2009 at 11:41 AM, Andrew U. Frank
i am not certain, if my code runs agains any version, but i fear it is too restrictive to say >= "current version", which could exclude too much? testing against all previous versions of the packages seems complicated and very time consuming.
If you assume that the packages you depend on follow the PVP then you can specify a range of versions which should have a stable API. For instance, if you depend on a package A and you build it on you system with A-1.0.2 then you can specify "A >= 1.0.2 && < 1.1". You know it to work with A-1.0.2 and from the PVP you can assume that A's API will not change until A-1.1. The question is which packages follow the PVP. Regards, Roel