Allow query to be applied to an ast with Tree.fromTree

.gitignore

@@ -1 +1,2 @@
-node_modules/
+*.DS_Store
+node_modules/

.travis.yml

@@ -1,6 +1,8 @@
 language: node_js
 node_js:
-  - 0.12
   - 4
   - 6
   - 7
+  - 8
+  - 9
+

lib/tree.js

@@ -23,17 +23,40 @@ var escodegenOptionDefaults = {
   }
 };
 
-function Tree(source, escodegenOptions, acornOptions) {
-  this.acornOptionDefaults = _.extend({}, acornOptionDefaults, acornOptions);
-  this.comments = [];
-  this.tokens = [];
-  this.acornOptionDefaults.onComment = this.comments;
-  this.acornOptionDefaults.onToken = this.tokens;
-  this.tree = acorn.parse(source.toString(), this.acornOptionDefaults);
-  this.tree = escodegen.attachComments(this.tree, this.comments, this.tokens);
-  this.body = new Body(this.tree.body, this.acornOptionDefaults);
-  this.escodegenOptions = _.extend({}, escodegenOptionDefaults, escodegenOptions);
-}
+var Tree = module.exports = function Tree() {
+  this.acornOptions = undefined;
+  this.comments = undefined;
+  this.tree = undefined;
+  this.body = undefined;
+  this.escodegenOptions = undefined;
+};
+
+Tree.fromSource = function(source, escodegenOptions, acornOptions) {
+  var instance = new Tree();
+  instance.acornOptions = _.extend({}, acornOptionDefaults, acornOptions);
+  instance.comments = [];
+  instance.tokens = [];
+  instance.acornOptions.onComment = instance.comments;
+  instance.acornOptions.onToken = instance.tokens;
+  instance.tree = acorn.parse(source.toString(), instance.acornOptions);
+  instance.tree = escodegen.attachComments(instance.tree, instance.comments, instance.tokens);
+  instance.body = new Body(instance.tree.body, instance.acornOptions);
+  instance.escodegenOptions = _.extend({}, escodegenOptionDefaults, escodegenOptions);
+  return instance;
+};
+
+Tree.fromTree = function(tree, escodegenOptions, acornOptions) {
+  var instance = new Tree();
+  instance.acornOptions = _.extend({}, acornOptionDefaults, acornOptions);
+  instance.comments = [];
+  instance.tokens = [];
+  instance.acornOptions.onComment = instance.comments;
+  instance.acornOptions.onToken = instance.tokens;
+  instance.tree = tree;
+  instance.body = new Body(instance.tree.body, instance.acornOptions);
+  instance.escodegenOptions = _.extend({}, escodegenOptionDefaults, escodegenOptions);
+  return instance;
+};
 
 /**
  * Return the regenerated code string
@@ -110,7 +133,3 @@ Tree.prototype.verbatim = function (body) {
   Body.verbatims[token] = body;
   return '\'' + token + '\';';
 };
-
-module.exports = function (source, escodegenOptions, acornOptions) {
-  return new Tree(source, escodegenOptions, acornOptions);
-};