Databinding a function in Angular.js

In angular I found out you can bind a template to a function which returns an array, like this:

<div class="cal_row" id ="id_{{task.id}}" ng-repeat="task in calendar.filtered()">
  <div class="id">{{task.id}}</div>
      <div class="task">{{task.task}}</div>
  <div class="start">{{task.start}}</div>
  <div class="finish">{{task.finish}}</div>
</div>

It's pretty cool, because that way I can, for example, avoid having to keep a variable around just to maintain the filtered version of the data.

However, I also loose the binding with the original data: when the underlying data changes, I can't seem to get angular.js to spot the change, and update the view.

Is there a way to do that? I tried to find anything in the docs, but couldn't

Thanks a lot