gistfile1.js

/**
 * This defines a simple widget
 */
function simpleWidget(){};
simpleWidget.$tags = [
    {name: 'widget', value: {width: 1, height: 1}}
];

/**
 * This defines a more complex one that depends on other services
 */
function complexWidget(serviceA) {};
simpleWidget.$inject = ['serviceA'];
simpleWidget.$tags = [
    {name: 'widget', value: {width: 4, height: 2}},
    //...
]

/**
 * The widget manager receives ALL services that were tagged as "widgets"
 */
function widgetManager(widgets, $scope) {
    // Here widgets would contain 'simpleWidget' and 'complexWidget'
    for (var i = 0; i < widgets.length; i++) {
        // Display the widget
    }
}

widgetManager.$inject = ['$scope']
widgetManager.$inject.$tags = 'widget'