alues to
the search parameters for number <code>Nr</code>, description <code>Nm</code>
and price <code>Pr</code>. The Pilog query (the first argument to
<code>solve</code>) passes these values to the Pilog variables <code>@Nr</code>,
<code>@Nm</code> and <code>@Pr</code>. Ranges of values are always specified by
cons pairs, so <code>(1 . 4)</code> includes the numbers 1 through 4, while
<code>(NIL . 100.00)</code> includes prices from minus infinite up to one
hundred.

<p>The list of unification variables i