t parameter in a function's definition, and so on.
That protocol is fine when there is at most one parameter with a
default value, but when there are even a few useful defaults, the
positional interface becomes burdensome:</p>
<ul>
<li><div class="first compound">
<p class="compound-first">Since an argument's meaning is given by its position, we have to
choose an (often arbitrary) order for parameters with default
values, making some combinations of defaults unusable:</p>
<pre class="compound-middle literal