<span class="hljs-keyword">namespace</span> LinkedList<span class="hljs-punctuation">;</span>

<span class="hljs-keyword">interface</span>

<span class="hljs-keyword">uses</span>
  System.Text<span class="hljs-punctuation">;</span>

<span class="hljs-keyword">type</span>
  List&lt;T&gt; = <span class="hljs-keyword">public</span> <span class="hljs-keyword">class</span>
    <span class="hljs-keyword">where</span> T <span class="hljs-keyword">is</span> Object<span class="hljs-punctuation">;</span>
  <span class="hljs-keyword">private</span>
    <span class="hljs-keyword">method</span> <span class="hljs-title function_">AppendToString</span><span class="hljs-params">(aBuilder: StringBuilder)</span>;
  <span class="hljs-keyword">public</span>
    <span class="hljs-keyword">constructor</span><span class="hljs-params">(aData: T)</span>;
    <span class="hljs-keyword">constructor</span><span class="hljs-params">(aData: T; aNext: List&lt;T&gt;)</span>;
    <span class="hljs-keyword">property</span> Next: List&lt;T&gt;<span class="hljs-punctuation">;</span>
    <span class="hljs-keyword">property</span> Data: T<span class="hljs-punctuation">;</span>

    <span class="hljs-keyword">method</span> <span class="hljs-title function_">ToString</span>: string<span class="hljs-punctuation">;</span> <span class="hljs-keyword">override</span><span class="hljs-punctuation">;</span>
  <span class="hljs-keyword">end</span><span class="hljs-punctuation">;</span>

<span class="hljs-keyword">implementation</span>

<span class="hljs-keyword">constructor</span> <span class="hljs-title function_">List</span>&lt;<span class="hljs-title function_">T</span>&gt;<span class="hljs-params">(aData: T)</span>;
<span class="hljs-keyword">begin</span>
  Data := aData<span class="hljs-punctuation">;</span>
<span class="hljs-keyword">end</span><span class="hljs-punctuation">;</span>

<span class="hljs-keyword">constructor</span> <span class="hljs-title function_">List</span>&lt;<span class="hljs-title function_">T</span>&gt;<span class="hljs-params">(aData: T; aNext: List&lt;T&gt;)</span>;
<span class="hljs-keyword">begin</span>
  <span class="hljs-keyword">constructor</span><span class="hljs-params">(aData)</span>;
  Next := aNext<span class="hljs-punctuation">;</span>
<span class="hljs-keyword">end</span><span class="hljs-punctuation">;</span>

<span class="hljs-keyword">method</span> <span class="hljs-title function_">List</span>&lt;<span class="hljs-title function_">T</span>&gt;.<span class="hljs-title function_">ToString</span>: string<span class="hljs-punctuation">;</span>
<span class="hljs-keyword">begin</span>
  <span class="hljs-keyword">with</span> lBuilder := <span class="hljs-keyword">new</span> StringBuilder <span class="hljs-keyword">do</span> <span class="hljs-keyword">begin</span>
    AppendToString(lBuilder)<span class="hljs-punctuation">;</span>
    <span class="hljs-keyword">result</span> := lBuilder.ToString()<span class="hljs-punctuation">;</span>
  <span class="hljs-keyword">end</span><span class="hljs-punctuation">;</span>
<span class="hljs-keyword">end</span><span class="hljs-punctuation">;</span>

<span class="hljs-keyword">method</span> <span class="hljs-title function_">List</span>&lt;<span class="hljs-title function_">T</span>&gt;.<span class="hljs-title function_">AppendToString</span><span class="hljs-params">(aBuilder: StringBuilder)</span>;
<span class="hljs-keyword">begin</span>
  <span class="hljs-keyword">if</span> assigned(Data) <span class="hljs-keyword">then</span>
    aBuilder.Append(Data.ToString)
  <span class="hljs-keyword">else</span>
    aBuilder.Append(<span class="hljs-string">&#x27;nil&#x27;</span>)<span class="hljs-punctuation">;</span>

  <span class="hljs-keyword">if</span> assigned(Next) <span class="hljs-keyword">then</span> <span class="hljs-keyword">begin</span>
    aBuilder.Append(<span class="hljs-string">&#x27;, &#x27;</span>)<span class="hljs-punctuation">;</span>
    Next.AppendToString(aBuilder)<span class="hljs-punctuation">;</span>
  <span class="hljs-keyword">end</span><span class="hljs-punctuation">;</span>
<span class="hljs-keyword">end</span><span class="hljs-punctuation">;</span>

<span class="hljs-keyword">end</span>.