From 6abda95a99f1dc03b15f33930f6f42fc050eeeac Mon Sep 17 00:00:00 2001
From: David Majda <david@majda.cz>
Date: Wed, 14 Apr 2010 21:08:35 +0200
Subject: [PATCH] Made regexps generated for empty character classes ("[]" and
 "[^]") work in IE.

---
 lib/compiler.js | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/lib/compiler.js b/lib/compiler.js
index 678fd3c..2b82e0b 100644
--- a/lib/compiler.js
+++ b/lib/compiler.js
@@ -734,6 +734,18 @@ PEG.Grammar.Literal.prototype.compile = function(resultVar) {
 };
 
 PEG.Grammar.Class.prototype.compile = function(resultVar) {
+  /*
+   * Stupid IE considers regexps /[]/ and /[^]/ syntactically invalid, so we
+   * translate them into euqivalents it can handle.
+   */
+  if (this._characters === "") {
+    var regexp = "/^(?!)/";
+  } else if (this._characters === "^") {
+    var regexp = "/^[\\S\\s]/";
+  } else {
+    var regexp = "/^[" + this._characters + "]/";
+  }
+
   return PEG.Compiler.formatCode(
     "if (this._input.substr(this._pos).match(${regexp}) !== null) {",
     "  var ${resultVar} = this._input[this._pos];",
@@ -746,7 +758,7 @@ PEG.Grammar.Class.prototype.compile = function(resultVar) {
     "}",
     {
       characters: this._characters,
-      regexp:     "/^[" + this._characters + "]/",
+      regexp:     regexp,
       resultVar:  resultVar
     }
   );