code: public VarSetBuilder varSetAtPath( String[] path)
      {
      VarSet varSet = null;
      if( path != null && path.length > 0)
        {
        varSet = new VarSet( path[0]);
        varSet_.addMember( varSet);
  
        for( int i = 1; i < path.length; i++)
          {
          VarSet child = new VarSet( path[i]);
          varSet.addMember( child);
          varSet = child;
          }
        }
  
      return
        varSet == null
        ? null
        : new VarSetBuilder( varSet);
      }
docs: Adds a new {@link VarSet} with the given path name and returns a builder
  for the new <CODE>VarSet</CODE>.