title: set-like products of ranges for queries etc
body: <p>Is there a nice way to write something like this:</p>
  
  <pre><code>foreach ((i,j) in PRODUCTOF(Range1, Range2))
  </code></pre>
  
  <p>or</p>
  
  <pre><code>PRODUCTOF(Range1, Range2).Sum((i,j) =&gt; i+17*j)
  </code></pre>
  
  <p>where PRODUCTOF is the unknown thing to me. </p>
  
  <p>Of course, you could circumvent this or write a function for this, but maybe there is a build-in syntax that one should prefer.</p>