title: C++ vector literals, or something like them
body: <p>I'm writing some code against a C++ API that takes vectors of vectors of vectors, and it's getting tedious to write code like the following all over the place:</p>
  
  <pre><code>vector&lt;string&gt; vs1;
  vs1.push_back("x");
  vs1.push_back("y");
  ...
  vector&lt;string&gt; vs2;
  ...
  vector&lt;vector&lt;string&gt; &gt; vvs1;
  vvs1.push_back(vs1);
  vvs1.push_back(vs2);
  ...
  vector&lt;vector&lt;string&gt; &gt; vvs2;
  ...
  vector&lt;vector&lt;vector&lt;string&gt; &gt; &gt; vvvs;
  vvvs.push_back(vvs1);
  vvvs.push_back(vvs2);
  ...
  </code></pre>
  
  <p>Does C++ have a vector literal syntax? I.e., something like:</p>
  
  <pre><code>vector&lt;vector&lt;vector&lt;string&gt;&gt;&gt; vvvs = 
      { { {"x","y", ... }, ... }, ... }
  </code></pre>
  
  <p>Is there a non-builtin way to accomplish this?</p>