From d1fc16c3736b8e0f6709731d667df5babece2b53 Mon Sep 17 00:00:00 2001
From: David Majda <david@majda.cz>
Date: Sat, 22 May 2010 17:43:32 +0200
Subject: [PATCH] Fix bug causing incorrect error messages

The bug could cause the list of expected strings in an error message to
contain strings that shouldn't be there.

Closes #2.
---
 lib/compiler.js    | 4 ++++
 lib/metagrammar.js | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/lib/compiler.js b/lib/compiler.js
index 752d647..1dcdcc9 100644
--- a/lib/compiler.js
+++ b/lib/compiler.js
@@ -915,6 +915,10 @@ PEG.Compiler = {
       "    },",
       "    ",
       "    _matchFailed: function(failure) {",
+      "      if (this._pos < this._rightmostMatchFailuresPos) {",
+      "        return;",
+      "      }",
+      "      ",
       "      if (this._pos > this._rightmostMatchFailuresPos) {",
       "        this._rightmostMatchFailuresPos = this._pos;",
       "        this._rightmostMatchFailuresExpected = [];",
diff --git a/lib/metagrammar.js b/lib/metagrammar.js
index ea0b4d6..f1566c3 100644
--- a/lib/metagrammar.js
+++ b/lib/metagrammar.js
@@ -36,6 +36,10 @@ PEG.grammarParser = (function(){
     },
     
     _matchFailed: function(failure) {
+      if (this._pos < this._rightmostMatchFailuresPos) {
+        return;
+      }
+      
       if (this._pos > this._rightmostMatchFailuresPos) {
         this._rightmostMatchFailuresPos = this._pos;
         this._rightmostMatchFailuresExpected = [];