title: Tools to support live coding as in Bret Victor's "Inventing on Principle" talk
body: <p>I've watched an already well known <a href="http://vimeo.com/36579366">video</a> where Bret Victor, former Apple UI designer shows amazing demos with immediate updates of running code after changing literally one symbol in source code. </p>
  
  <p>To make my question clear to those who haven't seen or don't have time to watch the video: I want to use a tool like that to write my own software. Is the tool he was demonstrating available, or are there other similar tools? </p>
  
  <p>It doesn't matter which languages/environments, I just want to have my code running and then change a line in source and immediately see the results updated without restarting it.</p>
  
  <p>The video is also available on <a href="http://www.youtube.com/watch?v=PUv66718DII">YouTube</a>, and the key points are:</p>
  
  <ul>
  <li><a href="https://youtu.be/PUv66718DII?t=3m30s">03:30</a> - 05:30 - Live coding a graphical algorithm (space)</li>
  <li><a href="https://youtu.be/PUv66718DII?t=11m">11:00</a> - 14:30 - Live coding some game code (space &amp; time)</li>
  <li><a href="https://youtu.be/PUv66718DII?t=17m30s">17:30</a> - 21:30 - Live coding local variables (state)</li>
  </ul>