ssignment as a powerful tool and dealt with some of the complex problems it raises.</li>
<li>Now we will consider another approach to modeling state, using data structures called <em>streams</em>.</li>
<li>We want to avoid identifying time in the computer with time in the modeled world.</li>
<li>If <span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>x</mi></mrow><annotation encoding="application/x-tex">x</annotation></semantics></math></span><span class="katex-html" aria-hidden="true">