title: Can Emacs AC mode (autocomplete) mode be configured to ignore numbers?
body: <p>I frequently include numerical data, phone numbers, etc. when typing text files, and this creates an annoyance with AC mode. Now when I type "2" I get an autocomplete option with every number or numerical code I have ever typed starting with "2". Not very helpful to say the least.</p>
  
  <p>I went in and cleaned out my <code>ac-comphist.dat</code>, but it just gets polluted with numbers again. Is there a way to prevent these entries from being added in the first place, perhaps with a regexp filter? I tried setting the variable <code>ac-ignores</code> with a list of integers, but it doesn't seem to have fixed the problem. </p>