_showLink first attempt

	  override def qlApply(inv:Invocation):QValue = {
	    for (
	      pt <- inv.contextTypeAs[URLableType];
	      // Problem 1: List
	      elemContext <- inv.contextElements;
	      // Problem 2: Option
	      elemV <- elemContext.value.firstOpt;
	      // Problem 3: another Option
	      url <- pt.getURL(elemContext)(elemV);
	      paramVal <- inv.processParam(0, elemContext);
	      label = paramVal.wikify(elemContext);
	      wikitext = QWikitext("[") + label + QWikitext(s"]($url)")
	    )
	      yield QValue.make(ExactlyOne, ParsedTextType, wikitext)
	  }