Once you have installed the various GHC compilers from HVR's PPA, you can do cabal configure --with-compiler=ghc-7.10.3 etc Alan On 13 March 2017 at 10:28, Ertugrul Söylemez wrote:

...

Someone asked to add support in my lib for older version of GHC. I know that there are GHC-version specific pragmas to activate the code on specific version.

I'm not quite sure how to setup the environment to use several GHCs. How do you do that kind of thing?

You can do it quite easily with Nix (which you can use alongside your normal package manager without interference, if you're not on NixOS). Type in your package's root directory:

cabal2nix --shell > shell.nix

Then you can build your package with various compiler versions:

nix-build shell.nix --argstr compiler ghc803 nix-build shell.nix --argstr compiler ghc7103 nix-build shell.nix --argstr compiler ghcjs

If a build is successful, you will get a symlink called 'result', which points to an installed version if your package including documentation. Once you're done testing, just delete that link.

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There are a bunch of compat libraries such as base-compat and transformers-compat that will make your life a lot easier, having to maintain CPP yourself is very error prone. HTH, Adam On Mon, 13 Mar 2017 at 09:41 Alan & Kim Zimmerman wrote:

See also https://github.com/edsko/ghc-dump-tree/blob/master/buildall.sh

On 13 March 2017 at 10:34, Alan & Kim Zimmerman wrote:

Once you have installed the various GHC compilers from HVR's PPA, you can do

cabal configure --with-compiler=ghc-7.10.3

etc

Alan

On 13 March 2017 at 10:28, Ertugrul Söylemez wrote:

...

Someone asked to add support in my lib for older version of GHC. I know that there are GHC-version specific pragmas to activate the code on specific version.

I'm not quite sure how to setup the environment to use several GHCs. How do you do that kind of thing?

You can do it quite easily with Nix (which you can use alongside your normal package manager without interference, if you're not on NixOS). Type in your package's root directory:

cabal2nix --shell > shell.nix

Then you can build your package with various compiler versions:

nix-build shell.nix --argstr compiler ghc803 nix-build shell.nix --argstr compiler ghc7103 nix-build shell.nix --argstr compiler ghcjs

If a build is successful, you will get a symlink called 'result', which points to an installed version if your package including documentation. Once you're done testing, just delete that link.

_______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.

_______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.