On Tue, Oct 28, 2008 at 7:56 AM, Reiner Pope
I've tried it out and it looks good so far. I had to fiddle with haskell-src-ext's .cabal file to get it to install with GHC 6.10, which is surprising since it isn't listed as a broken package... ah well.
Care to tell me what the problem is? I have no problem installing it with GHC 6.10, in fact the 0.3.9 version on hackage was uploaded solely to have it compile with both old and new GHC.
Unfortunately, I've uncovered a problem in the parser. For instance, with your module, [$hs|1+1*2|] evaluates to 4 rather than 3. This seems to be a general problem with infix operators, which I believe arises since haskell-src-exts isn't given the fixity declarations for + and *, so it doesn't know to bind (*) tighter than (+). I don't see how this problem can even be resolved without modifying Template Haskell: given that the operators reside in user code, there is no way to find their fixity.
Yes, you're right, haskell-src(-exts) does not handle fixity of operators for you. You need to collect the fixities yourself and make a second pass over expressions to get them right. This is definitely functionality I would like to see available in haskell-src-exts (though not on by default), so if anyone were to implement it I would gladly accept patches. Cheers, /Niklas