Add to/from functions using Boehm-Berarducci encodings

[jwiegley]

This would allow simple-conduit and other streaming representations (machines, conduit, io-streams) to interoperate with the pipes library.

I would like for simple-conduit to serve as both a "starter kit" for users interested in the pipes idea, and as a substitute for those who don't need the additional feature (i.e., a "no frills" option), since it offers excellent performance, simpler types, and directly employs function composition and application. I've also formally proven the category and type class laws, so it fits well into pipes' philosophical atmosphere of correctness-first.

Key to this would be a way to seamlessly integrate simple-conduit, which should be possible with such translation functions on on a Boehm-Berarducci encoding (which is what simple-conduit uses under the hood).

[Gabriella439]

One minor thing: is it okay if this functionality goes in pipes-extras? The main reason is that I am trying to stay underneath 150 exported names for pipes (the threshold after which Haddock creates an alphabetical index).

[jwiegley]

@Gabriel439 Certainly, that does sound more appropriate.

[Gabriella439]

Okay, I finally got around to adding these to pipes-extras. You can find the diff here:

Gabriella439/Haskell-Pipes-Extras-Library@95b3346

Take a look at that and let me know if that works for you.