title: Numerical hash for comparing lexical similarity
body: <p>Is there some form of hashing algorithm that produces similar numerical values for similar words? I imagine there would be a number of false positives, but it seems like something that could be useful for search pruning.</p>
  
  <p>EDIT: Soundex is neat and may come in handy, but ideally, I want something that behave something like this: <code>abs(f('horse') - f('hoarse')) &lt; abs(f('horse') - f('goat'))</code></p>