diff --git a/lib/javascript/gflib.js b/lib/javascript/gflib.js
index 20247ef2f..f64fa5f12 100644
--- a/lib/javascript/gflib.js
+++ b/lib/javascript/gflib.js
@@ -126,9 +126,38 @@ Linearizer.prototype.linearizeToTerm = function (tree) {
 
 /* Utilities */
 
+/* from Remedial JavaScript by Douglas Crockford, http://javascript.crockford.com/remedial.html */
 function isString(a) { return typeof a == 'string'; }
 function isArray(a) { return a && typeof a == 'object' && a.constructor == Array; }
 function isUndefined(a) { return typeof a == 'undefined'; }
+function isBoolean(a) { return typeof a == 'boolean'; }
+function isNumber(a) { return typeof a == 'number' && isFinite(a); }
+
+function dumpObject (obj) {
+	if (isUndefined(obj)) {
+		return "undefined";
+	} else if (isString(obj)) {
+		return '"' + obj.toString() + '"'; // FIXME: escape
+	} else if (isBoolean(obj) || isNumber(obj)) {
+		return obj.toString();
+	} else if (isArray(obj)) {
+		var x = "[";
+		for (var i = 0; i < obj.length; i++) {
+			x += dumpObject(obj[i]);
+			if (i < obj.length-1) {
+				x += ",";
+			}
+		}
+		return x + "]";		
+	} else {
+		var x = "{";
+		for (var y in obj) {
+			x += y + "=" + dumpObject(obj[y]) + ";" ;
+		}
+		return x + "}";
+	}
+}
+
 
 function copy_arguments(args, start) {
 	var arr = new Array();