title: Converting lowercase letters to capitals
body: <p>I am a newbie in Haskell and have some problem of defining a function that would convert all small letters to capital and leave the rest intact.</p>
  
  <p>I tried solving this question in my book so far:</p>
  
  <pre><code>capitalise :: String -&gt; String
  capitalise xs = [capitalise2 ch| ch&lt;-xs]
  
  capitalise2 :: Char -&gt; Char
  capitalise2 ch 
      | isLower ch    = chr (ord ch - 32)
      | otherwise    = ch
  </code></pre>
  
  <p>I am getting errors:</p>
  
  <pre><code>p3.hs:6:7: Not in scope: `isLower'
  p3.hs:6:23: Not in scope: `chr'
  p3.hs:6:28: Not in scope: `ord'
  </code></pre>
  
  <p>Any help would be much appreciated.</p>