Macro to derive ordering for case class

[johnynek]

@jcoveney

What we want is this:

case class MyClass(name: String, age: Int)

object MyClass {
def ordering = deriveOrdering[MyClass]
def monoid = deriveMonoid[MyClass]
}

[jcoveney]

Ordering is extremely easy. I'll put that in a patch the bijection
(assuming we get the other in nudge nudge)

What semantics do we want the monoid one to have? To be identical to the
rest ie treat it like a Tuple? Should be trivial as well. But I'm not sure
how to deal with the deps. It would ideally use some of the code I've
developed in the bijection code... It's not a ton so I could copy it. But
that feels lame. Thoughts on how we wanna manage deps for this stuff?

[avibryant]

What's wrong with depending on bijection? To start with just use the bijection to tuple, the tuple monoid, then back again. (In fact is there not an implicit bijection monoid that does this already?)

[jcoveney]

There is no bijection from any case class to tuple, but you're right, with
the bijection I am working on in bijection it should just work

[jcoveney]

Actually with the bijection code I think I can make a converter for any
type class!! Keep your eyes peeled tomorrow...

[jcoveney]

twitter/bijection#179 + twitter/bijection#183 provide a very nice way to get these for free.

[Trevoke]

@jcoveney Is it tomorrow yet?

[johnynek]

This was done.

See this wiki page here:
https://github.com/twitter/scalding/wiki/Automatic-Orderings%2C-Monoids-and-Arbitraries

[Trevoke]

Thanks :)

On Tue, Oct 4, 2016 at 1:51 PM P. Oscar Boykin [email protected]
wrote:

Closed #1054 #1054.

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