As much as I applaud your effort:

1. The GHC team advise users to install the Haskell Platform instead, which especially makes sense since lots of packages were moved out of GHC itself and onto for 6.12. Is it wise to still use the non-platform, no-batteries-included version with a smaller "set of libraries that are known to work together?"
2. The package is marked as an installer for 10.5 on i386, and as far as I recall the 64 bit problems of GHC haven't been solved as of 6.12.1, so will this GHC even work (produce usable binaries) on x86_64 Snow Leopard machines?

Thanks for the kind words. To answer your questions:

1. The Haskell Platform currently only provides GHC 6.10.4, and there's been a number of interesting developments to GHC since then. With a working cabal command-line tool (New formula: Cabal 0.8.0 #816), it's easy to install any Haskell package, and to brew up a Platform of your own.
2. GHC on OS X currently does not emit 64-bit code; it only generates 32-bit binaries, which work fine on my x86_64 Snow Leopard machine. The earlier, more serious problem has been fixed.

Thanks for your answers, having cabal-install available and #3400 fixed upstream definitely alleviate my concerns.

Looks great. We are starting to prefer binary downloads for large projects, so unless there is good reason, we'll merge this one rather than the other source based formula in the issue tracker.

One thing, you should use the parametised versions of safe_system and system. Otherwise any paths with spaces in will break this build. Thanks.

Thanks for the comments. I think using the prebuilt binary makes a lot of sense for GHC, since the build process takes a fair amount of time and space (more than 1GB of RAM).

I updated the formula to use parameterized versions of system calls (2b2ae21b0b75d90753eccc7e8b7933387a38b1ed).

This formula needs a "skip_clean: 'lib'" line or ghci will fail to run as follows:

% ghci
GHCi, version 6.12.1: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
ghc: 
/usr/local/Cellar/ghc/6.12.1/lib/ghc/base-4.2.0.0/HSbase-4.2.0.0.o: unknown symbol `_environ'
Loading package base ... linking ... ghc: unable to load package `base'

Once we stop stripping the object files in lib/, ghci works just fine:

% ghci
GHCi, version 6.12.1: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package ffi-1.0 ... linking ... done.
Prelude> 

Thanks!

Indeed it does. I pushed a fix to my fork (824fdfa).

Pushed 824fdfa

GHC now supports 64-bit on OSX, could the formula be updated to use an appropriate arch?

@QwertyManiac: With the update to GHC 7.0.3, brew install --64bit ghc gives me a GHC that builds 64-bit binaries. Is there something beyond this that you wanted?

Nope, that's it @Sharpie. I did not know of the explicit --64bit handle (could that be made automatic if unspecified?).

@QwertyManiac It appears that the 64 bit version is flagged as experimental---it won't become a default until the community considers it stable and battle-tested.

The brew options command can help you discover which switches a given formula will react to during installation. Just run brew options <formula name> to get a list of available choices.

@Sharpie - Got it, thanks for the help! :)

I updated the GHC formula to 7.2.1 (2dc4aff) and submitted a pull request (#6979).

No need to mention it in this old closed thread; we'll see the new pull requests.