title: String split returns nil value error in lua
body: <p>I'm following a <a href="http://lua-users.org/wiki/SplitJoin" rel="nofollow">lua doc page</a> on string splitting, get an error trying it myself. For example,</p>
  
  <pre><code>Lua 5.1.4  Copyright (C) 1994-2008 Lua.org, PUC-Rio
  split("a,b,c", ",") 
  </code></pre>
  
  <p>returns</p>
  
  <pre><code>stdin:1: attempt to call global 'split' (a nil value)
  stack traceback:
  stdin:1: in main chunk
  [C]: ?
  </code></pre>
  
  <p>Why is this so?</p>