[Haskell-cafe] GHC 6.12 on OS X 10.5

[Antoine Latter]

On Mon, Dec 21, 2009 at 3:43 PM, Tom Tobin <korpios at korpios.com> wrote:
>
> This time the install died on HJScript:
>
> **********
> [ 2 of 26] Compiling HJScript.Monad   ( src/HJScript/Monad.hs,
> dist/build/HJScript/Monad.o )
>
> src/HJScript/Monad.hs:51:10:
>    A pattern match on a GADT requires -XGADTs
>    In the pattern: EmptyBlock
>    In the definition of `mappend': mappend EmptyBlock b = b
>    In the instance declaration for `Monoid (Block ())'
> cabal: Error: some packages failed to install:
> HJScript-0.4.5 failed during the building phase. The exception was:
> ExitFailure 1
> **********
>
> I have no idea what to do next, so I'll probably bring this particular
> issue up on the Happstack list next.
>

This one I can help with. You need to modify the .cabal file for
HJScript slightly. To do this:

 cabal unpack HJScript
 cd HJScript-0.4.5
 ${EDITOR} HJScript.cabal

And then add 'GADTs' to the 'Extensions:' list.

Antoine