From 6ee59cd46e5735a0c10fdad039d1f6f6950ad32f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Fri, 10 Mar 2017 23:56:06 +0100
Subject: [PATCH] Prevent leakage of bundled Acorn into window.acorn

And fix Acorn loading under load.js
---
 src/core/PaperScript.js | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/src/core/PaperScript.js b/src/core/PaperScript.js
index 9f95fe53..b27e341d 100644
--- a/src/core/PaperScript.js
+++ b/src/core/PaperScript.js
@@ -15,18 +15,31 @@
  * @namespace
  */
 Base.exports.PaperScript = function() {
-    // Locally turn of exports and define for inlined acorn.
-    // Just declaring the local vars is enough, as they will be undefined.
-    var exports, define,
-        acorn = this.acorn;
-    // Try importing an outside version of acorn first, and fall back on the
-    // internal v0.5, which is kept at that version of small size, for now.
-    if (typeof require !== 'undefined') {
+    // `this` == global scope, as the function is called with `.call(this);`
+    var global = this,
+        // See if there is a global Acorn in the browser already.
+        acorn = global.acorn;
+    // Also try importing an outside version of Acorn, and fall back on the
+    // internal v0.5.0, which is kept at that version of small size, for now.
+    if (!acorn && typeof require !== 'undefined') {
         try { acorn = require('acorn'); } catch(e) {}
     }
+    // If no Acorn was found, load the bundled version.
     if (!acorn) {
-/*#*/ include('../../node_modules/acorn/acorn.min.js', { exports: false });
-        acorn = this.acorn;
+        // Provide our own local exports and module object so that Acorn gets
+        // assigned to it and ends up in the local acorn object.
+        var exports, module;
+        acorn = exports = module = {};
+/*#*/ include('../../node_modules/acorn/acorn.js', { exports: false });
+        // Clear object again if it wasn't loaded here; for load.js, see below.
+        if (!acorn.version)
+            acorn = null;
+    }
+
+    function parse(code, options) {
+        // NOTE: When using load.js, Acorn will end up in global.acorn and will
+        // not be immediately available, so we need to check for it here again:
+        return (acorn || global.acorn).parse(code, options);
     }
 
     // Operators to overload
@@ -96,10 +109,6 @@ Base.exports.PaperScript = function() {
 
     // AST Helpers
 
-    function parse(code, options) {
-        return acorn.parse(code, options);
-    }
-
     /**
      * Compiles PaperScript code into JavaScript code.
      *