docs: function extractAttribs( def ) {
      var key, val, attribs = { standard: {}, special: {}, implicit: [] };
      for ( key in def ) {
          val = def[ key ];
          if ( RX_INTEGER.test( key ) ) {
              attribs.implicit.push( val );
          } else if ( RX_STD_ATT.test( key ) ) {
              attribs.standard[ key ] = val;
          } else {
              attribs.special[ key ] = val;
          }
      }
      return attribs;
  }