From 2b319bef2faf0b52fd48bb56881051186603e9b1 Mon Sep 17 00:00:00 2001
From: tomhuda <tomhuda@strobecorp.com>
Date: Mon, 14 Feb 2011 16:05:01 -0800
Subject: [PATCH 1/2] Make the function passed to a block helper have an
 identical signature to top-level template methods

---
 lib/handlebars/vm.js |  9 ++++++---
 spec/qunit_spec.js   | 31 +++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/lib/handlebars/vm.js b/lib/handlebars/vm.js
index 5dca8479..3f44a36f 100644
--- a/lib/handlebars/vm.js
+++ b/lib/handlebars/vm.js
@@ -627,13 +627,16 @@ Handlebars.JavaScriptCompiler = function() {};
 Handlebars.VM = {
   programWithDepth: function(fn) {
     var args = Array.prototype.slice.call(arguments, 1);
-    return function(context) {
+    return function(context, helpers, partials, data) {
+      args[0] = helpers || args[0];
+      args[1] = partials || args[1];
+      args[2] = data || args[2];
       return fn.apply(this, [context].concat(args));
     };
   },
   program: function(fn, helpers, partials, data) {
-    return function(context) {
-      return fn(context, helpers, partials, data);
+    return function(context, h2, p2, d2) {
+      return fn(context, h2 || helpers, p2 || partials, d2 || data);
     };
   },
   noop: function() { return ""; },
diff --git a/spec/qunit_spec.js b/spec/qunit_spec.js
index 7dcac84e..7ec0cf2e 100644
--- a/spec/qunit_spec.js
+++ b/spec/qunit_spec.js
@@ -599,5 +599,36 @@ test("passing in data to a compiled function that expects data - works with bloc
   equals("#win happy world?", result);
 });
 
+test("you can override inherited data when invoking a helper", function() {
+  var template = Handlebars.compile("{{#hello}}{{world zomg}}{{/hello}}", true);
+
+  var helpers = {
+    hello: function(fn) {
+      return fn({exclaim: "?", zomg: "world"}, null, null, {adjective: "sad"});
+    },
+    world: function(thing, data) {
+      return data.adjective + " " + thing + (this.exclaim || "");
+    }
+  };
+
+  var result = template({exclaim: true, zomg: "planet"}, helpers, null, {adjective: "happy"});
+  equals("sad world?", result);
+});
 
 
+test("you can override inherited data when invoking a helper with depth", function() {
+  var template = Handlebars.compile("{{#hello}}{{world ../zomg}}{{/hello}}", true);
+
+  var helpers = {
+    hello: function(fn) {
+      return fn({exclaim: "?"}, null, null, {adjective: "sad"});
+    },
+    world: function(thing, data) {
+      return data.adjective + " " + thing + (this.exclaim || "");
+    }
+  };
+
+  var result = template({exclaim: true, zomg: "world"}, helpers, null, {adjective: "happy"});
+  equals("sad world?", result);
+});
+

From 32d7e52182414ae48ff82d4456d982049f0203a5 Mon Sep 17 00:00:00 2001
From: tomhuda <tomhuda@strobecorp.com>
Date: Fri, 25 Feb 2011 23:01:11 -0800
Subject: [PATCH 2/2] Helpers take precedence over context properties with the
 same name. This is useful in scenarios where your context object is inherited
 from another system (such as a framework or JSON API) that may contain
 properties that conflict with helpers you explicitly define.

---
 lib/handlebars/vm.js | 20 +++++++++++++-------
 spec/qunit_spec.js   | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 7 deletions(-)

diff --git a/lib/handlebars/vm.js b/lib/handlebars/vm.js
index 3f44a36f..1c2b4eef 100644
--- a/lib/handlebars/vm.js
+++ b/lib/handlebars/vm.js
@@ -8,7 +8,7 @@ Handlebars.JavaScriptCompiler = function() {};
   Compiler.OPCODE_MAP = {
     appendContent: 1,
     getContext: 2,
-    lookupWithFallback: 3,
+    lookupWithHelpers: 3,
     lookup: 4,
     append: 5,
     invokeMustache: 6,
@@ -25,7 +25,7 @@ Handlebars.JavaScriptCompiler = function() {};
   Compiler.MULTI_PARAM_OPCODES = {
     appendContent: 1,
     getContext: 1,
-    lookupWithFallback: 1,
+    lookupWithHelpers: 1,
     lookup: 1,
     invokeMustache: 2,
     pushString: 1,
@@ -201,7 +201,7 @@ Handlebars.JavaScriptCompiler = function() {};
 
       this.opcode('getContext', id.depth);
 
-      this.opcode('lookupWithFallback', id.parts[0] || null);
+      this.opcode('lookupWithHelpers', id.parts[0] || null);
 
       for(var i=1, l=id.parts.length; i<l; i++) {
         this.opcode('lookup', id.parts[i]);
@@ -432,11 +432,17 @@ Handlebars.JavaScriptCompiler = function() {};
       }
     },
 
-    lookupWithFallback: function(name) {
+    lookupWithHelpers: function(name) {
       if(name) {
-        this.pushStack(this.nameLookup('currentContext', name, 'context'));
-        var topStack = this.topStack();
-        this.source.push("if(" + topStack + " === undefined) { " + topStack + " = " + this.nameLookup('helpers', name, 'helper') + "; }");
+        var topStack = this.nextStack();
+
+        var toPush =  "if('" + name + "' in helpers) { " + topStack +
+                      " = " + this.nameLookup('helpers', name, 'helper') +
+                      "; } else { " + topStack + " = " +
+                      this.nameLookup('currentContext', name, 'context') +
+                      "; }";
+
+        this.source.push(toPush);
       } else {
         this.pushStack("currentContext");
       }
diff --git a/spec/qunit_spec.js b/spec/qunit_spec.js
index 7ec0cf2e..01c1aba0 100644
--- a/spec/qunit_spec.js
+++ b/spec/qunit_spec.js
@@ -632,3 +632,47 @@ test("you can override inherited data when invoking a helper with depth", functi
   equals("sad world?", result);
 });
 
+test("helpers take precedence over same-named context properties", function() {
+  var template = Handlebars.compile("{{goodbye}} {{cruel world}}");
+
+  var helpers = {
+    goodbye: function() {
+      return this.goodbye.toUpperCase();
+    }
+  };
+
+  var context = {
+    cruel: function(world) {
+      return "cruel " + world.toUpperCase();
+    },
+
+    goodbye: "goodbye",
+    world: "world"
+  };
+
+  var result = template(context, helpers);
+  equals(result, "GOODBYE cruel WORLD");
+});
+
+test("helpers take precedence over same-named context properties", function() {
+  var template = Handlebars.compile("{{#goodbye}} {{cruel world}}{{/goodbye}}");
+
+  var helpers = {
+    goodbye: function(fn) {
+      return this.goodbye.toUpperCase() + fn(this);
+    }
+  };
+
+  var context = {
+    cruel: function(world) {
+      return "cruel " + world.toUpperCase();
+    },
+
+    goodbye: "goodbye",
+    world: "world"
+  };
+
+  var result = template(context, helpers);
+  equals(result, "GOODBYE cruel WORLD");
+});
+