title: In what contexts do programming languages make real use of an Infinity value?
body: <p>So in Ruby there is a trick to specify infinity:</p>
  
  <pre><code>1.0/0
  =&gt; Infinity
  </code></pre>
  
  <p>I believe in Python you can do something like this</p>
  
  <pre><code>float('inf')
  </code></pre>
  
  <p>These are just examples though, I'm sure most languages have infinity in some capacity. When would you actually use this construct in the real world? Why would using it in a range be better than just using a boolean expression? For instance</p>
  
  <pre><code>(0..1.0/0).include?(number) == (number &gt;= 0) # True for all values of number
  =&gt; true
  </code></pre>
  
  <p>To summarize, what I'm looking for is a real world reason to use Infinity.</p>
  
  <p><strong>EDIT</strong>: I'm looking for real world code. It's all well and good to say this is when you "could" use it, when have people <em>actually</em> used it.</p>