title: R: Equivalent command to Matlab's keyboard function?
body: <p>Does <strong>R</strong> provide a similar command for debugging like Matlab's <a href="http://www.mathworks.com/help/matlab/ref/keyboard.html" rel="nofollow"><code>keyboard</code></a>?</p>
  
  <p>This command provides an interactive shell and can be used in any function.
  This gives access to all variables allowing one to verify that the input data is really what it should be (or test why it's not working as expected).</p>
  
  <p>Makes debugging a lot easier (at least in Matlab...).</p>