On Mar 21, 2018, at 11:34 PM, Luke Lau <luke_lau@icloud.com> wrote:

https://summer.haskell.org/ideas.html#format-preserving-yaml
Would this new library aim to also use the C library behind the scenes, or would there be more interest in making a completely native Haskell version? (Do FFI calls in Haskell have any performance overhead?)

If it's possible to do this using the C library behind the scenes then I don't see any reason not that. That said, my understanding is that the C library doesn't support this use case, so it's likely you'd have to write a pure Haskell implementation.