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scala sbt with pk11 or steps

I am quite frustrated with sbt and pk11/steps (Why are these things never work out of the box for me?)

I am just trying to run "jetty-run", but i got so many dependency errors, it's not fun anymore.

I am stuck with unresolved dependencies for sjson 0.3

Does anyone know which mvn repo can I get sjson 0.3 from?

Weird scala snippet in sjson (macro?)

I was taking a look at the source code of sjson when I discovered this weird piece of code:

<#list 2..22 as i> 
<#assign typeParams><#list 1..i as j>T${j}<#if i !=j>,</#if></#list></#assign>

  def asProduct${i}[S, ${typeParams}](<#list 1..i as j>f${j}: String<#if i != j>,</#if></#list>)(apply : (${typeParams}) => S)(unapply : S => Product${i}[${typeParams}])(implicit <#list 1..i as j>bin${j}: Format[T${j}]<#if i != j>,</#if></#list>) = new Format[S]{
    def writes(s: S) = {
      val product = unapply(s)
      JsObject(
        List(
          <#list 1..i as j>
          (tojson(f${j}).asInstanceOf[JsString], tojson(product._${j}))<#if i != j>,</#if>
          </#list>
        ))
    }
    def reads(js: JsValue) = js match {
      case JsObject(m) => // m is the Map
        apply(
          <#list 1..i as j>
          fromjson[T${j}](m(JsString(f${j})))<#if i != j>,</#if>
          </#list>
        )
      case _ => throw new RuntimeException("object expected")
    }
  }  
  </#list>

At first sight, it looks like a macro but I'm not sure because the ones I have seen are different and they modify Scala AST using classes like WeakTypeTag and so on. I know that this method is generating asProduct methods with 20 different parameters list. However, when I copy this piece of code in my REPL it's not parsed correctly and I get the following error:

<console>:1: error: identifier expected but double literal found.

And a pile of more errors.

I would like to know:

• Why and how this method works
• More resources to learn to master this
• Why in other libraries they don't use it and they prefer to copy/paste the methods manually (is there actually a reason for this or maybe they don't know its existence?)