title: how to generate "for loop" in YAML file
body: <p>suppose we have the following YAML </p>
  
  <pre><code>a:
    - s1: p
    - s2: p
    - s3: p
    - s4: p
  </code></pre>
  
  <p>is there a syntax using for loop to generate this YAML file</p>
  
  <p>like:</p>
  
  <pre><code>enum: [s1,s2,s3,s4]
  a:
  for t in enum:
    -t:p
  </code></pre>
  
  <p>writing a script is a way to do this. Is this feasible?</p>