title: Using Boost.Spirit to extract certain tags/attributes from HTML
body: <p>So I've been learning a bit about Boost.Spirit to replace the use of regular expressions in a lot of my code. The main reason is pure speed. I've found Boost.Spirit to be up to 50 times faster than PCRE for some relatively simple tasks.</p>
  
  <p>One thing that is a big bottleneck in one of my apps is taking some HTML, finding all "img" tags, and extracting the "src" attribute.</p>
  
  <p>This is my current regex:</p>
  
  <pre><code>(?i:&lt;img\s[^\&gt;]*src\s*=\s*[""']([^&lt;][^""']+)[^\&gt;]*\s*/*&gt;)
  </code></pre>
  
  <p>I've been playing around with it trying to get something to work in Spirit, but so far I've come up empty. Any tips on how to create a set of Spirit rules that will accomplish the same thing as this regex would be awesome.</p>