title: Control.Category, what does >>> and <<< mean?
body: <p>I am following <a href="https://lstephen.wordpress.com/2008/02/14/a-simple-haskell-web-server/" rel="noreferrer">this blog</a>, to write a simple http server in haskell,</p>
  
  <p>Usage of <code>&gt;&gt;&gt;</code> is not clear to me. What does this code snippet do?</p>
  
  <pre><code>handleHttpConnection r c = runKleisli
      (receiveRequest &gt;&gt;&gt; handleRequest r &gt;&gt;&gt; handleResponse) c &gt;&gt;
      close c
  </code></pre>
  
  <p>Similary on <a href="http://newartisans.com/2012/10/arrows-are-simpler-than-they-appear/" rel="noreferrer">this link</a>, i am seeing <code>&lt;&lt;&lt;</code></p>
  
  <pre><code>let h =     arr (++ "!")
            &lt;&lt;&lt; arr foo
            &lt;&lt;&lt; Kleisli bar
            &lt;&lt;&lt; arr id
  </code></pre>
  
  <p>What does <code>&lt;&lt;&lt;</code> and <code>&gt;&gt;&gt;</code> do? (<a href="http://hackage.haskell.org/package/base-4.8.0.0/docs/Control-Category.html" rel="noreferrer">Hackage document</a> is very concise and couldn't get much out of it.)</p>