Look at `greencard`

[edsko]

I believe greencard is long since defunct, but it might nonetheless be useful to take a brief look to see if there any ideas there that we could/should incorporate. According to an old blogpost by ezyang, it supports

• Automatic generation of foreign import based on the Haskell type signature (indeed, this is a major philosophical difference),
• A more comprehensive marshalling language,
• Automatic generation of data marshalling using Data Interface schemes.

so does at least sound relevant.