We recently completed a two-year redesign of Sigma, one of our spam-fighting systems. Check out how we integrated Haskell with our existing C++ code and the improvements we made to GHC.
Source: Fighting spam with Haskell | Engineering Blog | Facebook Code
Another interesting experience report, highlighting Haskell’s suitability for being used as a rapidly-evolving rules engine. Almost makes me wish Haskell were more amenable to embedding.
