You can use that to replace code by monkey patching<p><pre><code>    $ cat hi.rb 
    def method
      puts &quot;hi&quot;
    end
    method
    load(&quot;hello.rb&quot;)
    method

    $ cat hello.rb 
    def method
      puts &quot;hello&quot;
    end

    $ ruby hi.rb 
    hi
    hello
</code></pre>
You must engineer your application to execute the load method and that&#x27;s it.
However I wonder if this is really equivalent to what Erlang does. I remember <a href="http:&#x2F;&#x2F;rvirding.blogspot.it&#x2F;2008&#x2F;01&#x2F;virdings-first-rule-of-programming.html" rel="nofollow">http:&#x2F;&#x2F;rvirding.blogspot.it&#x2F;2008&#x2F;01&#x2F;virdings-first-rule-of-p...</a>