What does the double backslash mean in a function parameter in Elixir? : <p>I recently came across a code snippet such as:</p>

<pre><code>def loop(ring_pid \\ self, nil, true) do
  #some code 
end
</code></pre>

<p>What do the double backslashes mean?  I googled around and found <a href="http://elixir-lang.org/getting-started/sigils.html" rel="noreferrer">http://elixir-lang.org/getting-started/sigils.html</a>, but that applies to regular expressions not function params.</p>
