On 8/30/12 10:26 AM, Erik Hesselink wrote:
Note that this does not work if you want to support multiple versions of GHC, and might not work in general, since
* The hiding of catch is needed for preludes that still have it, since otherwise it will probably conflict with the one from Control.Exception. * Older versions do not have constructors for the FFI types, leading to warnings (or errors, I'm not sure).
In 6.12, they're warnings. And those warnings only show up with -Wall enabled. Though there does not appear to be an appropriate -fno-warn-foo to disable only these warnings while leaving the rest of -Wall intact. (If anyone knows of such a flag in 6.12, I'd be much obliged.)
* Packages might not work with the new bytestring version, since the API has breaking changes (although they're supposed to be minor).
For the first two, you need to add some CPP, for the last, you need actual testing.
Actually, that can be more problematic than you suspect. In particular, hsc2hs does not play nicely with Cabal's MIN_VERSION_foo(1,2,3) macros. So if you're using hsc2hs, which is common for certain FFI uses, then you have to put up with the warnings or rely on the __GLASGOW_HASKELL__ macro in lieu of the MIN_VERSION_foo(1,2,3) macros. It's doable, but it's uglier and more hackish than it ought to be. -- Live well, ~wren