Allow function arguments to with and each

Via @mcdan
Fixes #239

dist/handlebars.js

@@ -124,6 +124,9 @@ Handlebars.registerHelper('each', function(context, options) {
   var fn = options.fn, inverse = options.inverse;
   var i = 0, ret = "", data;
 
+  var type = toString.call(context);
+  if(type === functionType) { context = context.call(this); }
+
   if (options.data) {
     data = Handlebars.createFrame(options.data);
   }
@@ -168,6 +171,9 @@ Handlebars.registerHelper('unless', function(conditional, options) {
 });
 
 Handlebars.registerHelper('with', function(context, options) {
+  var type = toString.call(context);
+  if(type === functionType) { context = context.call(this); }
+
   if (!Handlebars.Utils.isEmpty(context)) return options.fn(context);
 });
 

dist/handlebars.runtime.js

@@ -124,6 +124,9 @@ Handlebars.registerHelper('each', function(context, options) {
   var fn = options.fn, inverse = options.inverse;
   var i = 0, ret = "", data;
 
+  var type = toString.call(context);
+  if(type === functionType) { context = context.call(this); }
+
   if (options.data) {
     data = Handlebars.createFrame(options.data);
   }
@@ -168,6 +171,9 @@ Handlebars.registerHelper('unless', function(conditional, options) {
 });
 
 Handlebars.registerHelper('with', function(context, options) {
+  var type = toString.call(context);
+  if(type === functionType) { context = context.call(this); }
+
   if (!Handlebars.Utils.isEmpty(context)) return options.fn(context);
 });
 

lib/handlebars/base.js

@@ -101,6 +101,9 @@ Handlebars.registerHelper('each', function(context, options) {
   var fn = options.fn, inverse = options.inverse;
   var i = 0, ret = "", data;
 
+  var type = toString.call(context);
+  if(type === functionType) { context = context.call(this); }
+
   if (options.data) {
     data = Handlebars.createFrame(options.data);
   }
@@ -145,6 +148,9 @@ Handlebars.registerHelper('unless', function(conditional, options) {
 });
 
 Handlebars.registerHelper('with', function(context, options) {
+  var type = toString.call(context);
+  if(type === functionType) { context = context.call(this); }
+
   if (!Handlebars.Utils.isEmpty(context)) return options.fn(context);
 });
 

spec/qunit_spec.js

@@ -797,6 +797,10 @@ test("with", function() {
   var string = "{{#with person}}{{first}} {{last}}{{/with}}";
   shouldCompileTo(string, {person: {first: "Alan", last: "Johnson"}}, "Alan Johnson");
 });
+test("with with function argument", function() {
+  var string = "{{#with person}}{{first}} {{last}}{{/with}}";
+  shouldCompileTo(string, {person: function() { return {first: "Alan", last: "Johnson"};}}, "Alan Johnson");
+});
 
 test("if", function() {
   var string   = "{{#if goodbye}}GOODBYE {{/if}}cruel {{world}}!";
@@ -861,6 +865,15 @@ test("each with @index", function() {
   equal(result, "0. goodbye! 1. Goodbye! 2. GOODBYE! cruel world!", "The @index variable is used");
 });
 
+test("each with function argument", function() {
+  var string = "{{#each goodbyes}}{{text}}! {{/each}}cruel {{world}}!";
+  var hash   = {goodbyes: function () { return [{text: "goodbye"}, {text: "Goodbye"}, {text: "GOODBYE"}];}, world: "world"};
+  shouldCompileTo(string, hash, "goodbye! Goodbye! GOODBYE! cruel world!",
+            "each with array function argument iterates over the contents when not empty");
+  shouldCompileTo(string, {goodbyes: [], world: "world"}, "cruel world!",
+            "each with array function argument ignores the contents when empty");
+});
+
 test("data passed to helpers", function() {
   var string = "{{#each letters}}{{this}}{{detectDataInsideEach}}{{/each}}";
   var hash = {letters: ['a', 'b', 'c']};