On Wed, Apr 16, 2014 at 2:05 AM, Michael Snoyman <michael@snoyman.com> wrote:

I still seem to be getting bug reports about the CPP implementation of Mavericks. Last I'd heard, it seemed that general consensus was that packages should *not* be patched to work around the different CPP implementation, and instead Mavericks users should be installing GCC's CPP.

Is this accurate? And is there a wiki page somewhere describing the situation and how to work around it? I'd like to have some authoritative URL to point people to, especially given that I have no access to a Mac system and therefore can't test this myself.

The correct answer is for ghc 7.8 to become established, because it removes the dependency on an external C preprocessor. Some of the reasons for this are:

- with FreeBSD 10 having moved to clang on x86 / x86_64, it is clearly only a matter of time before this becomes more than just a "Mavericks" issue;

- pretty much everyone *except* the Haskell community accepted that expecting cpp to handle anything other than C and derivatives was a mistake back when ANSI C came out;

- even with a K&R-style cpp like gcc -traditional, there are Haskell constructs that can break it; consider that it must know how to parse strings (there are some subtle differences between Haskell and C string syntax) and char constants (did you know that C allows multi-character (char) constants? and pretty much always has?) in order to know when to expand macros. With an ANSI cpp like clang's, it must also know when to interpret # and ## as splices.

brandon s allbery kf8nh sine nomine associates

allbery.b@gmail.com ballbery@sinenomine.net

unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net