title: Using foldl to return True if a list has only True values, otherwise false
body: <p>here is my code:</p>
  
  <pre><code>boolTrueList :: [Bool] -&gt; Bool
  boolTrueList xs
    | length (filterFalse xs) &gt; 0 = False
    | otherwise = True
    where
      filterFalse = filter (==False)
  </code></pre>
  
  <p>This is perfectly working, however I would like to rewrite the same thing with foldr/foldl, but I am stuck.</p>
  
  <p>My idea is to fold a list until I find a false value and then, stop.
  Any hint?</p>