ef" href="../glossary/#abstract_syntax_tree" markdown="1">abstract syntax tree</a></span> (AST)
whose nodes store information about what&rsquo;s in the program
(<a class="fig-ref" href="../style-checker/#style-checker-parse-tree">Figure 14.1</a>).
An AST is for a program what the <span class="ix-entry" ix-key="Document Object Model" markdown="1">DOM</span> is for HTML:
an in-memory representation that is easy for software to inspect and manipulate.</p>
<p>ASTs can be quite complex&mdash;for example,
the JSO