title: How to concatenate list into a string with separator in Haskell
body: <p>I need to write a function which takes a list and returns a concatenated string consisting of all strings from the input list, separated with spaces '', e.g.</p>
  <p><code>setTogether [&quot;aaa&quot;, &quot;bbb&quot;, &quot;c&quot;, &quot;cc&quot;] == &quot;aaa bbb c cc&quot;</code></p>
  <p><code>setTogether [&quot;aaa&quot;] == &quot;aaa&quot;</code></p>
  <p>with the type signature: <code>setTogether :: [String] -&gt; String</code></p>
  <pre><code>setTogether :: [String] -&gt; String
  setTogether ls = [x | x &lt;- ls]
  </code></pre>
  <p>^as you can see I'm kind of lost! Any help is greatly appreciated :)</p>
  <p>Edit: I'm not supposed to use &quot;words&quot; or &quot;unwords&quot;</p>