Add `encoder`?

[Gabriella439]

encoder :: (Monad m, Binary a) => Pipe a ByteString m r
encoder = for cat encode

This ties into https://github.com/k0001/pipes-binary/issues/12, where providing this will guide the user to the idiomatic solution for encoding.

If you're fine with this, then I can write it up into a pull request.

[Gabriella439]

I just realized that this doesn't type-check unless you generalize encode to be a Producer'. So that should be included as part of this proposal.

[k0001]

Producer' is fine, let's generalize that.

However, I'm not convinced we should export this function “as a convenience”, as it adds yet another function with the name “encode” in it to the library, which is a bit confusing. And if we add this, we probably should add encoderPut too so that you can use this function for types that lack a Binary instances.

My suggestion, instead, would be to add some documentation saying “use for cat encode to achieve this and that”. This is the same approach I used here: http://hackage.haskell.org/package/pipes-aeson-0.2.1/docs/Pipes-Aeson.html#v:encode

What do you think?

[Gabriella439]

Yeah, that works fine for me. Can you also add a short-cut fusion rule like this:

{-# RULES "p >-> for cat encode" forall p .
    p >-> for cat encode = for p encode
  #-}

[k0001]

I will. Thank you for that hint!

[k0001]

I've changed the docs and added the RULES in 194b91e, now in master. Thank you.

[Gabriella439]

Thanks to you, too!