From 26395a86fa008ebb5bcdff84bdcaf37d74655929 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Sun, 18 Jan 2015 18:23:03 +1100
Subject: [PATCH] add block scoped functions - fixes #514

---
 lib/6to5/transformation/transform.js          |  1 +
 .../spec-block-scoped-functions.js            | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+)
 create mode 100644 lib/6to5/transformation/transformers/spec-block-scoped-functions.js

diff --git a/lib/6to5/transformation/transform.js b/lib/6to5/transformation/transform.js
index 485ed26959..838ee5a90d 100644
--- a/lib/6to5/transformation/transform.js
+++ b/lib/6to5/transformation/transform.js
@@ -44,6 +44,7 @@ transform.moduleFormatters = {
 _.each({
   specNoForInOfAssignment:   require("./transformers/spec-no-for-in-of-assignment"),
   specSetters:               require("./transformers/spec-setters"),
+  specBlockScopedFunctions:  require("./transformers/spec-block-scoped-functions"),
 
   // playground
   malletOperator:            require("./transformers/playground-mallet-operator"),
diff --git a/lib/6to5/transformation/transformers/spec-block-scoped-functions.js b/lib/6to5/transformation/transformers/spec-block-scoped-functions.js
new file mode 100644
index 0000000000..814937fd31
--- /dev/null
+++ b/lib/6to5/transformation/transformers/spec-block-scoped-functions.js
@@ -0,0 +1,19 @@
+var t = require("../../types");
+
+exports.FunctionDeclaration = function (node, parent) {
+  if (t.isProgram(parent) || t.isExportDeclaration(parent)) {
+    return;
+  }
+
+  var declar = t.variableDeclaration("let", [
+    t.variableDeclarator(node.id, t.toExpression(node))
+  ]);
+
+  // hoist it up above everything else
+  declar._blockHoist = 2;
+
+  // todo: name this
+  node.id = null;
+
+  return declar;
+};