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
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