title: c++ Unpacking parameter pack from template arguments
body: <p>How to achieve want I want below?  The paramater pack I want to unpack is not in a function argument list but template argument list.</p>
  
  <pre><code>#include &lt;iostream&gt;
  #include &lt;array&gt;
  
  const std::size_t SIZE = 10;
  
  template &lt;int...ARGS&gt;
  std::array&lt;bool, SIZE&gt; func() {
      std::array&lt;bool, SIZE&gt; b;
      // I want to set b[n] = true, where n takes on all values from ARGS...
      // what to put in here???
      return b;
  }
  
  // Example of what I want to achieve:
  int main() {
      const std::array&lt;bool, SIZE&gt; b = func&lt;1,3,7&gt;();
      // I want b[1]==true, b[3]==true, b[7]==true, all others false
      for (int x: b) std::cout &lt;&lt; x &lt;&lt; std::endl;
  }
  </code></pre>
  
  <p>I have to use this form for func (instead of func(1,3,7)) to get my bigger program working (I'm dealing with multiple inheritance issues).</p>