easy way to replace term name in ast

Question

I have the following code for:

@compileTimeOnly("enable macro paradise to expand macro annotations")
class replace extends StaticAnnotation {
  def macroTransform(annottees: Any*) = macro replaceImpl.replace
}

object replaceImpl {
  def replace(c: Context)(annottees: c.Expr[Any]*): c.Expr[Any] = {
    import c.universe._

    // ? 

    c.Expr[Any](q"")
  }
}

Via this code, i want to replace variable name (x) in next example of usage:

@replace
def foo(x: Int) = x + 1 

it's simple method, but if i have a big method with many expression, what are the simpest way to replace variable name (from x to y for example)?

Answer 1

After some investigation, i need use Transfomer#transform method, some like this:

val t = new Transformer {
  override def transform(tree: Tree) = {
    val nt = tree match {
      case Ident(x) => Ident(someNewName)
      case x => x
    }
    super.transform(newTree)
  }
}

// and then

val result = t.transform(inputTree)