static void browseDir(File dir) {
  class Browser {
    L<Map> origData, data;
    File dir;
    JTable table;
    
    *(File dir) {
      browse(dir);
    }
    
    void browse(File path) {
      dir = path;
      origData = listDirAwarenessStyle(dir);

      data = sortedByField("Name", map(func(Map map) {
        putKeysFirst(renameKeys(map,
          "dir", "Directory?", "m", "Last modified",
          "n", "Name", "l", "File Size (Bytes)"),
          "Name", "Directory?")
      }, origData));
      
      S title = f2s(dir);
      bool firstTime = table == null;
      table = showTable(table, data, title);

      if (firstTime) {
        onDoubleClickOrEnter(table, voidfunc(int row) {
          Map map = getTableLineAsMap(table, row);
          if (map == null) ret;
          Map map2 = findByField(origData, "n", map.get("Name"));
          S name = getString(map, "Name");
          if (isTrue(_get(map2, "dir")))
            browse(new File(dir, name));
          else
            jShowFile(new File(dir, name));
        });
        
        registerKey(getFrame(table), KeyEvent.VK_BACK_SPACE, "Back", r {
          // TODO: list roots 
          File p = dir.getParentFile();
          if (p != null)
            browse(p);
        });
      }
    }
  }
  
  new Browser(dir);
}

Began life as a copy of #1004132