Talk: Case Study: Cross Compiling dhall-json

haskell.sg Meetup — March 2018

At the haskell.sg March Meetup I gave a short presentation on how to cross compile dhall-json to raspberry pi, and the issues you might run into. I wanted to show that it is possible to cross compile non-trivial Haskell packages today, and that issues (ghc-head, build-type, and Template Haskell) have mostly trivial fixes of which most can in principle be upsteamed.

The talk coincided with the release of GHC 8.4, and the release of a new zlib package to hackage, which renders the need to fix zlib unnecessary.

Note that while this works, the fix for contravariant is a rather crude one. For a proper fix and the complete set of patches see contravariant#44.