lker work?</h2>
<p>The AST walker uses the Visitor pattern,
but how does it actually work?
We can build our own by defining a class with methods that walk the tree,
take action depending on the kind of node,
and then go through the children of that node (if any).
The user can then derive a class of their own from this
and override the set of action methods they&rsquo;re interested in.</p>
<p>One key difference between our implementation and <code>acorn-walk</code>&rsquo;s is that
our methods don&rsquo;t nee