Q:

AngularJS + highlight.js (to evaluate string with expression in directive)

I am trying to create a highlight.js directive and I am having problems getting scope vars to apply.
<script src="http://code.jquery.com/jquery-1.8.2.min.js" ></script>
<link rel="stylesheet" href="http://yandex.st/highlightjs/7.3/styles/default.min.css">
<script src="http://yandex.st/highlightjs/7.3/highlight.min.js"></script>

<div ng-app="app">
    <div ng-controller="MyCtrl">
        <snippet>&lt;script src=&quot;{{src}}&quot;&gt;&lt;/script&gt;</snippet>
        {{src}}
    </div>
</div>

​
function MyCtrl($scope) {
  $scope.src = "foo.js";   
}

app.directive('snippet', ['$timeout', function($timeout) {
    var template = '<pre><code></code></pre>';

    return {
        restrict: 'E',
        compile: function(tElement, tAttrs, transclude) {

            var rawCode = tElement.text();
            tElement.html(template);

            return function(scope, element, attrs) {
                $timeout(function() {
                    scope.$apply(function() {
                        var formattedCode = hljs.highlightAuto(rawCode);
                        $(element).find('code').html(formattedCode.value);
                    });
                }, 0);
            }
        }
    }
}]);​

Here is the fiddle: http://jsfiddle.net/dkrotts/RE7Jj/5/
As you can see, $scope.src is not applying its value inside the snippet. What am I doing wrong?

A:

The key is you should use $interpolate instead of $compile

Description of $interpolate
Compiles a string with markup into an interpolation function. This
  service is used by the HTML $compile service for data binding. See
  $interpolateProvider for configuring the interpolation markup.

When you use $complie, it will turn your string into element. 

Description of $compile
Compiles a piece of HTML string or DOM into a template and produces a
  template function, which can then be used to link scope and the
  template together.

(To be honest, I don't really understand the description until trying it out.)
Here is the working plunk
app.controller('MainCtrl', function($scope) {
  $scope.cdnPath = "//path/to/cdn/";
  $scope.version = "1.0"; 
});

app.directive('snippet', ['$timeout', '$interpolate', function($timeout, $interpolate) {
    return {
        restrict: 'E',
        template:'<pre><code ng-transclude></code></pre>',
        replace:true,
        transclude:true,
        link:function(scope, elm, attrs){             
            var tmp =  $interpolate(elm.find('code').text())(scope);
             $timeout(function() {                
                elm.find('code').html(hljs.highlightAuto(tmp).value);
              }, 0);
        }
    };
}]);

