Edit in JSFiddle

var testapp = angular.module('testapp', []);

testapp.controller('parentController', ['$scope', '$window', function($scope, $window) {
    console.log('parentController scope id = ', $scope.$id);
    $scope.primary1Label = 'Prime1';
    
    $scope.onPrimary1Click = function() {
        $window.alert('Primary1 clicked');    
    };
}]);

testapp.directive('primary', function() {
    return {
        restrict: 'C',
        link: function(scope, element, attrs) {
            element.addClass('btn btn-primary');
        }
    }
});

testapp.directive('buttonBar', function() {
    return {
        restrict: 'EA',
        template: '<div class="span4 well clearfix"><div class="pull-right" ng-transclude></div></div>',
        replace: true,
        transclude: true
    };
});
<div ng-controller="parentController">    
    <button-bar>
        <button class="primary" ng-click="onPrimary1Click()">{{primary1Label}}</button>
        <button class="primary">Primary2</button>
    </button-bar>
</div>
.primary, .secondary {
    margin-left: 5px;
    margin-right: 5px;
}

External resources loaded into this fiddle: