@Override
public void process(RsPlan plan) throws RsParsingException{

      RsToken token;
      token = nextToken();
      if(!token.isIdentifier())
         throw token.gripe("Invalid syntax where units specification expected");
      String test = token.getString();
      if(test.equals("inches"))
         plan.setUnits(new RsInches());
      else if(test.equals("meters"))
         plan.setUnits(new RsMeters());
      else if(test.equals("feet"))
         plan.setUnits(new RsFeet());
      else
         throw token.gripe("Invalid or unimplemented units specification "+test);

      token = nextToken();
      if(token.isSemiColon())
         return;
      throw token.gripe("Invalid syntax where semi-colon expected");

   }