Meaning of version tags in cabal files

[Don Stewart]

red5_2:
> I noticed that cabal will parse, but ignore, version tags.  For example, the
> two lines appear to be equivalent in how a package gets built:
> 
> Version: 1.1
> Version: 1.1-alternate
> 
> Arguably this is not the right thing to do, as it changes the semantics of
> versions.  For example, I can install version 1.1 of a package without
> replacing version 1.0, but if I try to install version 1.0-alternate, I will
> actually replace version 1.0.
> 
> I'm not against discarding version tags, but I'd like to know if there's a
> rationale for _silently_ discarding them.

Version tags are not supported by Cabal or Hackage or any of the Haskell
tools, afaik.

See the package version policy for the conventions we follow:

    http://www.haskell.org/haskellwiki/Package_versioning_policy