feat($compile): support for dynamic template generation

`template` and `templateUrl` properties can now be optionally defined
via a function. This allows templates to be dynamically generated on
the fly.

docs/content/guide/directive.ngdoc

@@ -406,10 +406,18 @@ compiler}. The attributes are:
     migrates all of the attributes / classes from the old element to the new one. See the
     {@link guide/directive#Components Creating Components} section below for more information.
 
+    You can specify `template` as a string representing the template or as a function which takes
+    two arguments `tElement` and `tAttrs` (described in the `compile` function api below) and returns
+    a string value representing the template.
+
   * `templateUrl` - Same as `template` but the template is loaded from the specified URL. Because
     the template loading is asynchronous the compilation/linking is suspended until the template
     is loaded.
 
+    You can specify `templateUrl` as a string representing the URL or as a function which takes two
+    arguments `tElement` and `tAttrs` (described in the `compile` function api below) and returns
+    a string value representing the url.
+
   * `replace` - if set to `true` then the template will replace the current element, rather than
     append the template to the element.
 

src/ng/compile.js

@@ -652,9 +652,14 @@ function $CompileProvider($provide) {
           }
         }
 
-        if ((directiveValue = directive.template)) {
+        if (directive.template) {
           assertNoDuplicate('template', templateDirective, directive, $compileNode);
           templateDirective = directive;
+
+          directiveValue = (isFunction(directive.template))
+              ? directive.template($compileNode, templateAttrs)
+              : directive.template;
+
           directiveValue = denormalizeTemplate(directiveValue);
 
           if (directive.replace) {
@@ -977,11 +982,14 @@ function $CompileProvider($provide) {
           // The fact that we have to copy and patch the directive seems wrong!
           derivedSyncDirective = extend({}, origAsyncDirective, {
             controller: null, templateUrl: null, transclude: null, scope: null
-          });
+          }),
+          templateUrl = (isFunction(origAsyncDirective.templateUrl))
+              ? origAsyncDirective.templateUrl($compileNode, tAttrs)
+              : origAsyncDirective.templateUrl;
 
       $compileNode.html('');
 
-      $http.get(origAsyncDirective.templateUrl, {cache: $templateCache}).
+      $http.get(templateUrl, {cache: $templateCache}).
         success(function(content) {
           var compileNode, tempTemplateAttrs, $template;
 

test/ng/compileSpec.js

@@ -647,6 +647,32 @@ describe('$compile', function() {
       });
 
 
+      describe('template as function', function() {
+
+        beforeEach(module(function() {
+          directive('myDirective', valueFn({
+            replace: true,
+            template: function($element, $attrs) {
+              expect($element.text()).toBe('original content');
+              expect($attrs.myDirective).toBe('some value');
+              return '<div id="templateContent">template content</div>';
+            },
+            compile: function($element, $attrs) {
+              expect($element.text()).toBe('template content');
+              expect($attrs.id).toBe('templateContent');
+            }
+          }));
+        }));
+
+
+        it('should evaluate `template` when defined as fn and use returned string as template', inject(
+            function($compile, $rootScope) {
+          element = $compile('<div my-directive="some value">original content<div>')($rootScope);
+          expect(element.text()).toEqual('template content');
+        }));
+      });
+
+
       describe('templateUrl', function() {
 
         beforeEach(module(
@@ -1215,6 +1241,37 @@ describe('$compile', function() {
       });
 
 
+      describe('template as function', function() {
+
+        beforeEach(module(function() {
+          directive('myDirective', valueFn({
+            replace: true,
+            templateUrl: function($element, $attrs) {
+              expect($element.text()).toBe('original content');
+              expect($attrs.myDirective).toBe('some value');
+              return 'my-directive.html';
+            },
+            compile: function($element, $attrs) {
+              expect($element.text()).toBe('template content');
+              expect($attrs.id).toBe('templateContent');
+            }
+          }));
+        }));
+
+
+        it('should evaluate `templateUrl` when defined as fn and use returned value as url', inject(
+            function($compile, $rootScope, $templateCache) {
+          $templateCache.put('my-directive.html', '<div id="templateContent">template content</span>');
+          element = $compile('<div my-directive="some value">original content<div>')($rootScope);
+          expect(element.text()).toEqual('');
+
+          $rootScope.$digest();
+
+          expect(element.text()).toEqual('template content');
+        }));
+      });
+
+
       describe('scope', function() {
         var iscope;