 those variables should take.</p>
<p>Ranges are the simplest of the two.</p>
<pre><code>RANGES_ASSIGNMENTS ::= RANGES_ASSIGNMENT
                    |  RANGES_ASSIGNMENT ';' RANGES_ASSIGNMENTS
RANGES_ASSIGNMENT ::= RANGE_INDEX '&lt;-' RANGE_EXPRESSION</code></pre>
<p>where <code>RANGE_INDEX</code> is just a variable and <code>RANGE_EXPRESSION</code> an expression that should evaluate to a list or vector. You can specify more than one variable if these are separated by <code>;</code> or newlines (the grammar