parent data access with riot

gistfile1.html

<myparent>
  <div>{ list[2] ? list[2].e : list[0].a }</div>
  <mychild list={ list }></mychild>
  
  this.list = [{ a: 'b' }, { c: 'd' }]; 
</myparent>

<mychild>
  // any HTML here
  
  var parent = this.parent;
  
  this.someHandler = function() {
    opts.list.push({ e: 'f' });
    parent.update(); // HOW TO AVOID THIS?  
  }
</mychild>