nl_tokens: when a view is rendered in a buffer appending a child view will render that view and append the resulting buffer into its buffer .
pl_tokens: function ( view , childView , <mask> ) { var buffer = view . buffer , _childViews = view . _childViews ; childView = view . createChildView ( childView , options ) ; if ( ! _childViews . length ) { _childViews = view . _childViews = _childViews . slice ( ) ; } _childViews . push ( childView ) ; childView . renderToBuffer ( buffer ) ; view . propertyDidChange ( 'childViews' ) ; return childView ; }