Re: [Haskell-cafe] Conditional compilation for different versions of GHC?

On 1 December 2010 03:54, Michael Snoyman wrote:

On Wed, Dec 1, 2010 at 4:07 AM, Thomas Schilling wrote:

...

I think a nicer way to solve that issue is to use Cabal's MIN_VERSION macros.

 1. Add CPP to your extensions.  This will cause cabal to auto-generate a file with MIN_VERSION_<pkg> macros for each <pkg> in build-depends.

 2. GHC 6.12.* comes with template-haskell 2.4, so to test for that use:

#ifdef MIN_VERSION_template_haskell(2,4,0)  .. ghc-6.12.* code here. #endif

This should make it more transparent to the user.

Also, I think

#if GHC7 ... #endif

is more transparent than a check on template-haskell.

Note that in many cases it is inappropriate to use the ghc version as a proxy for a library version since most libraries are upgradable independently of GHC. Duncan