ezyang’s blog

This year at ICFP, we had some blockbuster attendance to the Haskell Implementor's Workshop (at times, it was standing room only). I had the pleasure of presenting the work I had done over the summer on Backpack.

You can grab the slides or view the presentation itself (thank you ICFP organizers for being incredibly on-the-ball with videos this year!) The talk intersects a little bit with my blog post A taste of Cabalized Backpack, but there are more pictures, and I also emphasize (perhaps a little too much) the long term direction we are headed in.

There were a lot of really nice talks at HiW. Here are some of my personal highlights:

• Richard Eisenberg: Dependent Haskell
• Alejandro Serrano: Interactive features in ghc-mod (lightning talk) (Heavily based off of Idris-mode)
• Lennart Augustsson: Better type-error messages (lightning talk) (Why isn’t this in GHC? The big problem is that the data type representing types is the same as the internal data type for types in Core. Tracking locations should be strictly at the surface syntax, so we’d have to refactor the frontend first.)
• Michael Adams: Extending "Optimize your SYB" (lightning talk) (In the original paper, they suggest speedups can be gained by aggressively evaluating expressions of type TypeRep, TyCon, Data and Typeable at compile time. Michael was wondering if there were any other types which should receive similar treatment. One audience-member suggested Int (i.e. to get rid of boxing), but I don’t find that very convincing.)