title: Calling omnicompletion for every keypress in vim
body: <p>I have a vim script that uses a one line window to get a filename pattern from the user. This pattern can be completed to a full filename from a database if you press CTRL-X CTRL-O. Now the only problem is that you have to press the auto completion shortcut by yourself. But I want the auto completion to work incrementally so that for every character you type it automatically gets updated (think about the CTRL-R file open dialog in Eclipse).</p>
  
  <p>Is there a way to use an autocommand or some kind of callback to call the function behind CTRL-X CTRL-O for each character the user is typing in this particular window?</p>