title: Is there a general way to prevent overflows when summing lists?
body: <p>I'm working with ByteStrings, and by extension a lot of Word8.
  When i write <code>sum word8List</code>, the returned value is also Word8, but i know my data, and that sum is too large for a Word8. Should i avoid sum, or does it work differently than i think?</p>
  
  <p>Is there some general function for summing numbers without overflowing, like <code>Num a =&gt; a -&gt; Integer</code>?</p>