WIP, but main extractor paths seem to work

This adds a possible macro for building JDBC type sources.

Right now just a size annotation, also might need an unsigned one.

Number of types available probably needs to increase. But it seems to build most of the info we would need for a source
Should have uploaded a set there. Uses implicit ordering to show up not
being able to build the implicit. We have it in our bijection tests. We can
add more runtime evals too but for this I think this gives full coverage

On Monday, December 22, 2014, P. Oscar Boykin <notifications@github.com>
wrote:

> In
> scalding-jdbc-macros/src/test/scala/com/twitter/scalding/jdbc/macros/MacrosUnitTests.scala
> <https://github.com/twitter/scalding/pull/1140#discussion-diff-22194607>:
>
> > +package com.twitter.scalding.jdbc.macros
> > +
> > +import org.scalatest.{ Matchers, WordSpec }
> > +
> > +import com.twitter.scalding._
> > +import com.twitter.scalding.jdbc.macros._
> > +
> > +import com.twitter.bijection.macros.{ IsCaseClass, MacroGenerated }
> > +
> > +case class User(
> > +  date_id: Int,
> > +  @size(64) user_name: String,
> > +  @size(64) email: String,
> > +  @size(64) password: String,
> > +  age: Option[Int],
> > +  @size(22) gender: String = "male")
>
> shapeless has some trick where you write the code in a string and you have
> a test that it won't compile.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/twitter/scalding/pull/1140/files#r22194607>.
>