following code shows how this works for multiple indexing of matrices.</p>
<pre><code>matrix[5,7] m;
...
row_vector[3] rv;
rv = m[4, 3:5];    // result is 1 x 3
...
vector[4] v;
v = m[2:5, 3];     // result is 3 x 1
...
matrix[3, 4] m2;
m2 = m[1:3, 2:5];  // result is 3 x 4</code></pre>
<p>The key is realizing that any position with a multiple index or
bounded index remains in play in the result, whereas any dimension
with a single index is replaced with 1 in the resulting dimensions.
Then the type of the r