title: Dart replacing the node in the abstract syntax tree
body: <p>i want to replace print(a) with print(a+b) in the following code.</p>
  
  <pre><code>void main(){
     String a ="hey";
     String b ="there"; 
     print(\$a);
  }
  </code></pre>
  
  <blockquote>
    <p>cn is the AstNode &amp; cn contains print($a)</p>
  </blockquote>
  
  <p>Is their any way i can do this? Please help me, i am new to dart.</p>