From 00abfd3164d76eb618caa1e167c66e2d69faee57 Mon Sep 17 00:00:00 2001
From: Alan Johnson <alan@commondream.net>
Date: Tue, 14 Sep 2010 20:37:03 -0400
Subject: [PATCH] Got handleExpression written up.

---
 lib/handlebars.js | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/lib/handlebars.js b/lib/handlebars.js
index 246043cd..e386f05c 100644
--- a/lib/handlebars.js
+++ b/lib/handlebars.js
@@ -166,17 +166,28 @@ var Handlebars = {
     }
   },
 
-  handleBlock: function(lookup, context, proxy, fn, notFn) {
+  handleBlock: function(lookup, context, arg, fn, notFn) {
     var out = "";
     if (Handlebars.isFunction(lookup)) {
-      out = out + lookup.call(context, proxy, fn);
+      out = out + lookup.call(context, arg, fn);
     }
     else if (typeof lookup != 'undefined') {
-      out = out + Handlebars.helperMissing.call(proxy, lookup, fn);
+      out = out + Handlebars.helperMissing.call(arg, lookup, fn);
     }
 
     if (notFn != null && Handlebars.isFunction(lookup.not)) {
-      out = out + lookup.not.call(context, proxy, notFn); 
+      out = out + lookup.not.call(context, arg, notFn); 
+    }
+
+    return out;
+  },
+
+  handleExpression: function(lookup, context, arg, isEscaped) {
+    var out = "";
+    if (Handlebars.isFunction(lookup)) {
+      out = out + Handlebars.filterOutput(lookup.call(context, arg), isEscaped);
+    } else if(!Handlebars.isEmpty(lookup)) {
+      out = out + Handlebars.filterOutput(lookup, isEscaped);
     }
 
     return out;
@@ -282,9 +293,10 @@ Handlebars.Compiler.prototype = {
   },
 
   addExpression: function(mustache, param) {
+    param = param || null; 
     var expr = this.lookupFor(mustache);
-    this.fn += "if (Handlebars.isFunction(" + expr + ")) out = out + Handlebars.filterOutput(" + expr + ".call(Handlebars.buildContext(context, stack), " + param + "), " + this.escaped + "); ";
-    this.fn += "else if(typeof " + expr + "!== 'undefined') out = out + Handlebars.filterOutput(" + expr + ", " + this.escaped + "); ";
+    this.fn += "var proxy = Handlebars.buildContext(context, stack);"
+    this.fn += "out = out + Handlebars.handleExpression(" + expr + ", proxy, " + param + ", " + this.escaped + ");";
   },
 
   addInvertedSection: function(mustache) {