iteration values from 0 up to <code>len(a)-1</code> and does not index into the array
or slice itself. For a <code>nil</code> slice, the number of iterations is 0.
</li>

<li>
For a string value, the "range" clause iterates over the Unicode code points
in the string starting at byte index 0.  On successive iterations, the index value will be the
index of the first byte of successive UTF-8-encoded code points in the string,