My requirements were a bit different than the ones asked on the original question, but hopefully I might help someone who is going through the same problem that I was..
I had to define if a field was required or not based on a scope variable.. So I basically had to set ng-required="myScopeVariable"
(which is a boolean variable).
<div class="align-left" ng-repeat="schema in schemas">
<input type="text" ng-required="schema.Required" />
</div>