On 07/14/2014 11:23 PM, Andrew Gibiansky wrote:
Hey all,
I would like to propose a very minor flag to add to GHC. I would like GHC to have a --with-prelude flag, which would specify an alternate Prelude to use instead of the default Haskell prelude.
This would have an effect similar to -XNoImplicitPrelude and an additional
import MyNewPrelude
in the source file. It might be a /little/ different semantically, as a qualified import would disable the original implicit import, just like it does with the default Haskell prelude.
To play devil's advocate, I don't think this is a good idea. It moves information that is fundamentally local (which library imports a module requires) into global state: magic flags that must be passed to the build system for anything to work. It would be super annoying for an {IDE, coworker, ...} to have to analyze your build system just to figure out which functions are in scope. We went down this road once before with -fglasgow-exts. Eventually, we all realized it was much better to place the required extensions in pragmas at the top of the file.