Re: [Haskell-cafe] The container problem

Andrew Coppin wrote:

If I understand this correctly, to solve this problem you need either Functional Dependencies or Associated Types. Is that correct?

A motivating example in papers on FD is exactly typeclasses for containers. Okasaki puts this into practice in the Edison library. Despite its comprehensiveness, elegance, and the Okasaki name brand, it did not become mainstream. I don't know why.