title: Convert fraction to float?
body: <p>Kind of <a href="https://stackoverflow.com/questions/95727/how-to-convert-floats-to-human-readable-fractions">like this question</a>, but in reverse.</p>
  
  <p>Given a string like <code>1</code>, <code>1/2</code>, or <code>1 2/3</code>, what's the best way to convert it into a float? I'm thinking about using regexes on a case-by-case basis, but perhaps someone knows of a better way, or a pre-existing solution. I was hoping I could just use <code>eval</code>, but I think the 3rd case prevents that.</p>