From 41ab47dde8928215e68647e276e18228048f6265 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Fri, 17 Oct 2014 11:09:49 +1100
Subject: [PATCH] allow let scope access within FunctionDeclaration, add
 _block-hoist helper transformer - fixes #77

---
 lib/6to5/transform.js                 |  3 ++-
 lib/6to5/transformers/_block-hoist.js | 17 +++++++++++++++++
 lib/6to5/transformers/let-scoping.js  | 19 ++++++++++++++++---
 lib/6to5/transformers/modules.js      | 19 +------------------
 4 files changed, 36 insertions(+), 22 deletions(-)
 create mode 100644 lib/6to5/transformers/_block-hoist.js

diff --git a/lib/6to5/transform.js b/lib/6to5/transform.js
index 6c8867fc52..8649b476ce 100644
--- a/lib/6to5/transform.js
+++ b/lib/6to5/transform.js
@@ -94,7 +94,8 @@ transform.transformers = {
   unicodeRegex:             require("./transformers/unicode-regex"),
   generators:               require("./transformers/generators"),
 
-  _aliasFunctions:          require("./transformers/_alias-functions")
+  _aliasFunctions:          require("./transformers/_alias-functions"),
+  _blockHoist:              require("./transformers/_block-hoist")
 };
 
 _.each(transform.transformers, function (transformer, key) {
diff --git a/lib/6to5/transformers/_block-hoist.js b/lib/6to5/transformers/_block-hoist.js
new file mode 100644
index 0000000000..8efe4108fd
--- /dev/null
+++ b/lib/6to5/transformers/_block-hoist.js
@@ -0,0 +1,17 @@
+exports.BlockStatement =
+exports.Program = {
+  exit: function (node) {
+    var unshift = [];
+
+    node.body = node.body.filter(function (bodyNode) {
+      if (bodyNode._blockHoist) {
+        unshift.push(bodyNode);
+        return false;
+      } else {
+        return true;
+      }
+    });
+
+    node.body = unshift.concat(node.body);
+  }
+};
diff --git a/lib/6to5/transformers/let-scoping.js b/lib/6to5/transformers/let-scoping.js
index fcf465cb1a..238946cde5 100644
--- a/lib/6to5/transformers/let-scoping.js
+++ b/lib/6to5/transformers/let-scoping.js
@@ -37,9 +37,22 @@ exports.VariableDeclaration = function (node, parent, file) {
       });
 
       if (letReferences.length) {
-        return b.callExpression(b.functionExpression(null, letReferences, b.blockStatement([
-          b.returnStatement(node)
-        ])), letReferences);
+        var callNode = function () {
+          return b.callExpression(b.functionExpression(null, letReferences, b.blockStatement([
+            b.returnStatement(node)
+          ])), letReferences);
+        };
+
+        if (node.type === "FunctionDeclaration") {
+          node.type = "FunctionExpression";
+          var declar = b.variableDeclaration("var", [
+            b.variableDeclarator(node.id, callNode())
+          ]);
+          declar._blockHoist = true;
+          return declar;
+        } else {
+          return callNode();
+        }
       } else {
         return false;
       }
diff --git a/lib/6to5/transformers/modules.js b/lib/6to5/transformers/modules.js
index 62928f0978..4e445d50d6 100644
--- a/lib/6to5/transformers/modules.js
+++ b/lib/6to5/transformers/modules.js
@@ -95,30 +95,13 @@ var pushExportDeclaration = function (node, parent, nodes) {
     nodes.push(declar);
 
     if (declar.type === "FunctionDeclaration") {
-      assign._modulesHoist = true;
+      assign._blockHoist = true;
     }
 
     nodes.push(assign);
   }
 };
 
-exports.Program = {
-  exit: function (node) {
-    var unshift = [];
-
-    node.body = node.body.filter(function (bodyNode) {
-      if (bodyNode._modulesHoist) {
-        unshift.push(bodyNode);
-        return false;
-      } else {
-        return true;
-      }
-    });
-
-    node.body = unshift.concat(node.body);
-  }
-};
-
 exports.ExportDeclaration = function (node, parent) {
   var nodes = [];