diff --git a/js/ArgParser.js b/js/ArgParser.js
index f4906e41a..3c886ccb1 100755
--- a/js/ArgParser.js
+++ b/js/ArgParser.js
@@ -16,8 +16,10 @@ Options and their defaults are:
 	noNames: false,
 	cascadeDefaults: false,
 	allowEval: true
+	sandbox: null
 	globals: null
 
+`sandbox` is the sandbox object used to evaluate JavaScript parameters
 `globals` is the global variable object provided to evaluated parameters
 
 \*/
@@ -26,9 +28,8 @@ Options and their defaults are:
 /*jslint node: true */
 "use strict";
 
-var sandbox = require("./Sandbox.js").sandbox;
-
 var ArgParser = function(argString,options) {
+	options = options || {};
 	var parseToken = function(match,p) {
 			var n;
 			if(match[p]) { // Double quoted
@@ -38,7 +39,7 @@ var ArgParser = function(argString,options) {
 			} else if(match[p+2]) { // Double-square-bracket quoted
 				n = match[p+2];
 			} else if(match[p+3]) { // Double-brace quoted
-				n = options.allowEval === false ? match[p+3] : sandbox(match[p+3],options.globals);
+				n = options.allowEval === false ? match[p+3] : options.sandbox.execute(match[p+3],options.globals);
 			} else if(match[p+4]) { // Unquoted
 				n = match[p+4];
 			} else if(match[p+5]) { // empty quote
diff --git a/js/Main.js b/js/Main.js
index 6a9e8a7d7..1aff3f947 100644
--- a/js/Main.js
+++ b/js/Main.js
@@ -14,6 +14,7 @@ var WikiStore = require("./WikiStore.js").WikiStore,
 	tiddlerInput = require("./TiddlerInput.js"),
 	tiddlerOutput = require("./TiddlerOutput.js"),
 	WikiTextProcessor = require("./WikiTextProcessor.js").WikiTextProcessor,
+	Sandbox = require("./Sandbox.js").Sandbox,
 	Navigators = require("./Navigators.js").Navigators,
 	StoryNavigator = require("./StoryNavigator.js").StoryNavigator;
 
@@ -58,6 +59,9 @@ for(t=0; t<tiddlers.length; t++) {
 	store.addTiddler(new Tiddler(tiddlers[t]));
 }
 
+// Set up the sandbox for evaluated macro parameters
+store.sandbox = new Sandbox(store.getTiddlerText("javascript.pegjs"));
+
 // Install the standard navigators
 var navigators = new Navigators({
 		document: document,
diff --git a/js/Recipe.js b/js/Recipe.js
index 00d564575..d31e9cc63 100755
--- a/js/Recipe.js
+++ b/js/Recipe.js
@@ -57,7 +57,7 @@ var Recipe = function(options,callback) {
 	this.recipeQueue = async.queue(function(task,callback) {
 		retrieveFile(task.filepath,task.contextPath,function(err,data) {
 			if(err) {
-				callback(err);
+				me.callback(err);
 			} else {
 				me.processRecipeFile(task.recipe,data.text,data.path);
 				callback(null);
@@ -342,7 +342,7 @@ Recipe.prototype.cookRss = function()
 		getRssTiddlers = function(sortField,excludeTag) {
 			var r = [];
 			me.store.forEachTiddler(sortField,excludeTag,function(title,tiddler) {
-				if(!tiddler.hasTag(excludeTag)) {
+				if(!tiddler.hasTag(excludeTag) && tiddler.fields.modified !== undefined) {
 					r.push(tiddler);
 				}
 			});
diff --git a/js/Sandbox.js b/js/Sandbox.js
index 3d8d8097a..db2d59df7 100644
--- a/js/Sandbox.js
+++ b/js/Sandbox.js
@@ -9,9 +9,13 @@ Execute a fragment of JavaScript in a sandbox
 /*jslint evil: true, node: true */
 "use strict";
 
-var uglify = require("uglify-js");
+var pegjs = require("pegjs");
 
-var sandbox = function(code,globals) {
+var Sandbox = function(parserText) {
+	this.parser = pegjs.buildParser(parserText);
+};
+
+Sandbox.prototype.execute = function(code,globals) {
 	var globalNames = [],
 		globalValues = [],
 		collectGlobals = function(globals) {
@@ -36,20 +40,20 @@ var sandbox = function(code,globals) {
 	out.push(code);
 	out.push(";})");
 	// Parse the code
-	var tree = uglify.parser.parse(out.join(""));
+	var code = out.join(""),
+		tree = this.parser.parse(out.join(""));
 	// XXX: Sanitise the code by checking for references to globals, stripping out eval()
-	// Recompile the code
-	var compiledCode = uglify.uglify.gen_code(tree);
+console.log(tree);
 	// Execute it
 	var result;
 	try {
-		result = eval(compiledCode).apply(null,globalValues);
+		result = eval(code).apply(null,globalValues);
 	} catch(err) {
 		result = "{{** Evaluation error: " + err + " **}}";
 	}
 	return result;
 };
 
-exports.sandbox = sandbox;
+exports.Sandbox = Sandbox;
 
 })();
\ No newline at end of file
diff --git a/js/WikiStore.js b/js/WikiStore.js
index 5962853b9..3e6d98e76 100755
--- a/js/WikiStore.js
+++ b/js/WikiStore.js
@@ -21,6 +21,7 @@ var WikiStore = function WikiStore(options) {
 	this.textProcessors = {};
 	this.tiddlerSerializers = {};
 	this.tiddlerDeserializers = {};
+	this.sandbox = options.sandbox;
 	this.shadows = options.shadowStore !== undefined ? options.shadowStore : new WikiStore({
 		shadowStore: null
 	});
diff --git a/js/WikiTextRenderer.js b/js/WikiTextRenderer.js
index 8a75dc494..c7815a490 100644
--- a/js/WikiTextRenderer.js
+++ b/js/WikiTextRenderer.js
@@ -134,7 +134,8 @@ WikiTextRenderer.prototype.executeMacro = function(macroNode,title) {
 			var argOptions = {
 				globals: {
 					title: title
-				}
+				},
+				sandbox: this.store.sandbox
 			};
 			for(var g in macroInfo.argOptions) {
 				argOptions[g] = macroInfo.argOptions[g];
diff --git a/parsers/split.recipe b/parsers/split.recipe
new file mode 100644
index 000000000..05c1d6cf1
--- /dev/null
+++ b/parsers/split.recipe
@@ -0,0 +1,3 @@
+tiddler: javascript.pegjs
+	title: javascript.pegjs
+	type: text/x-tiddlywiki-parser
diff --git a/tiddlywiki.js b/tiddlywiki.js
index ee58ca5f1..52dc933e7 100644
--- a/tiddlywiki.js
+++ b/tiddlywiki.js
@@ -107,8 +107,8 @@ var commandLineSwitches = {
 				recipe = new Recipe({
 					filepath: args[0],
 					store: store
-				},function() {
-					callback(null);
+				},function(err) {
+					callback(err);
 				});
 			}
 		}
diff --git a/tiddlywiki5/tiddlers/HelloThere.tid b/tiddlywiki5/tiddlers/HelloThere.tid
index 93a1218ff..9fba2824b 100644
--- a/tiddlywiki5/tiddlers/HelloThere.tid
+++ b/tiddlywiki5/tiddlers/HelloThere.tid
@@ -10,3 +10,5 @@ TiddlyWiki5 gains new capabilities through a [[completely rebuilt architecture|T
 TiddlyWiki5 also functions as the build system for earlier versions of TiddlyWiki, replacing the elderly Cook and Ginsu tools (see https://github.com/TiddlyWiki/cooker for details). See the CommandLineInterface for details.
 
 <<list all>>
+
+<<echo {{2+2}}>>
diff --git a/tiddlywiki5/tiddlywiki5.recipe b/tiddlywiki5/tiddlywiki5.recipe
index d9da3d54b..05e913a0f 100644
--- a/tiddlywiki5/tiddlywiki5.recipe
+++ b/tiddlywiki5/tiddlywiki5.recipe
@@ -3,6 +3,7 @@ copyright: ../copyright.txt
 style: styles.css
 
 recipe: tiddlers/split.recipe
+recipe: ../parsers/split.recipe
 
 jslib: ../test/tiddlywiki.2.6.5/source/tiddlywiki/jquery/jquery.js
 
@@ -22,14 +23,8 @@ jsmodule: ../js/Navigators.js
 jsmodule: ../js/StoryNavigator.js
 jsmodule: ../js/Main.js
 
-jsmodule: ../node_modules/uglify-js/lib/parse-js.js
-	title: lib/parse-js
-jsmodule: ../node_modules/uglify-js/lib/process.js
-	title: lib/process
-jsmodule: ../node_modules/uglify-js/lib/squeeze-more.js
-	title: lib/squeeze-more
-jsmodule: ../node_modules/uglify-js/uglify-js.js
-	title: uglify-js
+jsmodule: ../node_modules/pegjs/lib/peg.js
+	title: pegjs
 
 jsbootstart: BootStart.js
 jsbootend: BootLoader.js