add optional bluebird coroutine transformer - @phpnode

lib/6to5/file.js

@@ -95,6 +95,10 @@ File.prototype.getTransformers = function () {
   _.each(transform.transformers, function (transformer) {
     if (transformer.canRun(file)) {
       transformers.push(transformer);
+
+      if (transformer.manipulateOptions) {
+        transformer.manipulateOptions(file.opts, file);
+      }
     }
   });
 
@@ -144,6 +148,12 @@ File.prototype.parseShebang = function (code) {
   return code;
 };
 
+File.prototype.addImport = function (id, source) {
+  var specifiers = [t.importSpecifier(t.identifier("default"), id)];
+  var declar = t.importDeclaration(specifiers, t.literal(source));
+  this.ast.program.body.unshift(declar);
+};
+
 File.prototype.addDeclaration = function (name) {
   if (!_.contains(File.declarations, name)) {
     throw new ReferenceError("unknown declaration " + name);

lib/6to5/transformation/transform.js

@@ -49,6 +49,8 @@ _.each({
   memoizationOperator:       require("./transformers/playground-memoization-operator"),
   objectGetterMemoization:   require("./transformers/playground-object-getter-memoization"),
 
+  bluebirdCoroutines:        require("./transformers/optional-bluebird-coroutines"),
+
   react:                     require("./transformers/react"),
   modules:                   require("./transformers/es6-modules"),
   propertyNameShorthand:     require("./transformers/es6-property-name-shorthand"),

lib/6to5/transformation/transformer.js

@@ -5,11 +5,12 @@ var t        = require("../types");
 var _        = require("lodash");
 
 function Transformer(key, transformer, opts) {
-  this.experimental = !!transformer.experimental;
-  this.transformer  = Transformer.normalise(transformer);
-  this.optional     = !!transformer.optional;
-  this.opts         = opts || {};
-  this.key          = key;
+  this.manipulateOptions = transformer.manipulateOptions;
+  this.experimental      = !!transformer.experimental;
+  this.transformer       = Transformer.normalise(transformer);
+  this.optional          = !!transformer.optional;
+  this.opts              = opts || {};
+  this.key               = key;
 }
 
 Transformer.normalise = function (transformer) {

lib/6to5/transformation/transformers/optional-bluebird-coroutines.js

@@ -0,0 +1,30 @@
+var traverse = require("../../traverse");
+var t        = require("../../types");
+
+exports.manipulateOptions = function (opts) {
+  opts.experimental = true;
+  opts.blacklist.push("generators");
+};
+
+exports.optional = true;
+
+exports.Function = function (node, parent, file) {
+  if (!node.async || node.generator) return;
+
+  node.async = false;
+  node.generator = true;
+
+  traverse(node, {
+    enter: function (node) {
+      if (t.isFunction(node)) this.stop();
+
+      if (t.isAwaitExpression(node)) {
+        node.type = "YieldExpression";
+      }
+    }
+  });
+
+  var id = t.identifier("Bluebird");
+  file.addImport(id, "bluebird");
+  return t.callExpression(t.memberExpression(id, t.identifier("coroutine")), [node]);
+};

lib/6to5/transformation/transformers/optional-core-aliasing.js

@@ -9,9 +9,7 @@ exports.optional = true;
 exports.ast = {
   enter: function (ast, file) {
     file._coreId = file.generateUidIdentifier("core");
-    var specifiers = [t.importSpecifier(t.identifier("default"), file._coreId)];
-    var declar = t.importDeclaration(specifiers, t.literal("core-js/library"));
-    ast.program.body.unshift(declar);
+    file.addImport(file._coreId, "core-js/library");
   },
 
   exit: function (ast, file) {