Can anyone explain this context-free grammar to me?
<p>I need to understand this for a homework. You would not be giving me the answer by telling me this, you'd simply help me understand the question being asked.</p>

<p>I've read my class notes which haven't been very helpful, as well as searching all over the internet for context-free grammar info. I can't find anything that looks like what I've been given, and I'm very confused. </p>

<p>If anyone could tell me what this CFG describes, or give me a good resource to explain this subject, I would really appreciate it. </p>

<p>The CFG is this:</p>

<p>S is the starting symbol</p>

<pre><code>&lt;S&gt; → &lt;A&gt; | ε
&lt;A&gt; → 0&lt;B&gt; | 1&lt;A&gt;
&lt;B&gt; → 0&lt;C&gt; | 1&lt;B&gt;
&lt;C&gt; → 0&lt;D&gt; | 1&lt;C&gt;
&lt;D&gt; → 1&lt;D&gt; | 0&lt;B&gt; | ε
</code></pre>