VictorTaelin

A::B is a system with 4 tokens: `A#`, `#A`, `B#` and `#B`.

An A::B program is a sequence of tokens. Example:

    B# A# #B #A B#

To *compute* a program, we must rewrite neighbor tokens, using the rules:

    A# #A ... becomes ... nothing
    A# #B ... becomes ... #B A#

xeno-by

import scala.annotation.StaticAnnotation
import scala.reflect.macros.Macro
import language.experimental.macros

class body(tree: Any) extends StaticAnnotation

trait Macros extends Macro {
  import c.universe._

  def selFieldImpl = {