title: Haskell How to find next day?
body: <pre><code>-- | Days of week.
  data Day = Sunday | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday deriving (Eq, Show)
  
  -- | Returns the next weekday (excluding weekend, namely Saturday and Sunday).
  nextWeekday :: Day -&gt; Day
  nextWeekday day = 
    if x == Sunday
      then let x = Monday
    if x == Monday 
      then let x = Tuesday
    if x == Tuesday
      then let x = Wednesday
    if x == Wednesday
      then let x = Thursday
    if x == Thursday
      then let x = Friday
    if x == Friday
      then let x = Saturday
    else
      then let x = Sunday
  </code></pre>
  <p>This my code right now... What's wrong with this code...? How can I auto-indent the Haskell code?</p>