creating angular-js directive that updates ng-model

Question

I am trying to create a directive that wraps the twitter typeahead plugin. What I have so far is:

HTML:

<input ng-twitter-typeahead type="text" ng-model="participant" data="exampleData" />
{{ participant }}

I want the value for 'participant' to be updated when I select something on the typeahead. The typeahead itself works properly, but I can't capture the selected value. Below is the javascript:

var app = angular.module('myApp', [])
app.directive('ngTwitterTypeahead', function () {
  return {
    restrict: 'EA',
    scope: {
      data: '='
    },
    link: function ($scope, $element, $attrs) {
      $element.typeahead($scope.data);

      $element.bind('typeahead:selected', function(obj, datum) {        
         // I really don't know how to do this part
         // the variable 'datum' is what I want to be passed to ng-model
         // I tried things like:
            // Including the ngModelController and typing:
            // ngModel.$setViewValue(datum)
            // but that didn't work.
     }
  };
});

I'm obviously missing something fundamental when it comes to AngularJS. Any help would be greatly appreciated!

EDIT **

I found the solution. I am clueless sometimes:

angular.module('siyfion.ngTypeahead', [])
  .directive('ngTypeahead', function () {
    return {
    restrict: 'C',
    scope: {
      datasets: '=',
  ngModel: '='
    },
    link: function ($scope, $element, $attrs) {
      $element.typeahead($scope.datasets);      

      $element.bind('typeahead:selected', function(obj, datum) {        
    $scope.$apply(function() {
     $scope.ngModel = datum;
    });
  })            
    }
  };
});

Answer 1

You could require ngModel controller inside the directive. It will give you an access to the model controller inside the link function, see http://docs.angularjs.org/api/ng.directive:ngModel.NgModelController

Here you can find an example how to use it the real life http://suhairhassan.com/2013/05/01/getting-started-with-angularjs-directive.html#.UhSdDOZdXUE