title: What do the different brackets in Ruby mean?
body: <p>In Ruby, what's the difference between <code>{}</code> and <code>[]</code>?</p>
  
  <p><code>{}</code> seems to be used for both code blocks and hashes.</p>
  
  <p>Are <code>[]</code> only for arrays?</p>
  
  <p>The documention isn't very clear.</p>