Hi, I've now extended Hoogle to search the GHC API, as detailed in this blog post: http://neilmitchell.blogspot.com/2011/05/searching-ghc-with-hoogle.html As a simple example, to find out about the GHC register allocator, you can search for: http://haskell.org/hoogle/?hoogle=%2Bghc+alloc+reg Thanks, Neil