Also, Ruby has much more complicated rules for method dispatch.  Lua just has functions, and if you want to implement any more complicated dispatch, you have to do it yourself.  Once I implemented Ruby-like dispatch on top of Lua, and it was terribly slow:<p><a href="http://blog.reverberate.org/2009/02/09/disappointment/" rel="nofollow">http://blog.reverberate.org/2009/02/09/disappointment/</a><p>To make a long story short, porting my existing Lua project to use my Ruby-like method dispatch resulted in a 4x slowdown.