Seems to be that Wdired is just a hack that represents file and directory metadata in a textual format (in a buffer in Emacs parlance). It's not obvious to anyone that editing a filename in this buffer actually goes to the file system and changes the name of the file. It's even less obvious that removing rows removes files or directories. It actually sounds rather dangerous to use.

This is not functionality that emerges from some elegant design of Emacs, it seems it's just a hack.

  ```
  const lengthParam = (a) => {
    let count = 0;
    for(let c of a) {
        if(Array.isArray(c)) {
            count += lengthParam(c)
        }
        else {
            count++;
        }
    }
    return count;
  };
  ```