From b35d1c806e67f6eb69841e34b03f831f4ac5164e Mon Sep 17 00:00:00 2001
From: Glenn Maynard <gmaynard@users.sourceforge.net>
Date: Wed, 23 Feb 2005 06:17:29 +0000
Subject: [PATCH] fix LuaReference::operator= add LuaReference::IsNil

---
 stepmania/src/LuaReference.cpp | 16 +++++++++++++---
 stepmania/src/LuaReference.h   |  1 +
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/stepmania/src/LuaReference.cpp b/stepmania/src/LuaReference.cpp
index 00d3fd9e38..91b481b8df 100644
--- a/stepmania/src/LuaReference.cpp
+++ b/stepmania/src/LuaReference.cpp
@@ -42,9 +42,14 @@ LuaReference &LuaReference::operator=( const LuaReference &cpy )
 
 	Unregister();
 
-	/* Make a new reference. */
-	lua_rawgeti( LUA->L, LUA_REGISTRYINDEX, cpy.m_iReference );
-	m_iReference = luaL_ref( LUA->L, LUA_REGISTRYINDEX );
+	if( cpy.m_iReference == LUA_NOREF )
+		m_iReference = LUA_NOREF;
+	else
+	{
+		/* Make a new reference. */
+		lua_rawgeti( LUA->L, LUA_REGISTRYINDEX, cpy.m_iReference );
+		m_iReference = luaL_ref( LUA->L, LUA_REGISTRYINDEX );
+	}
 
 	return *this;
 }
@@ -72,6 +77,11 @@ bool LuaReference::IsSet() const
 	return m_iReference != LUA_NOREF;
 }
 
+bool LuaReference::IsNil() const
+{
+	return m_iReference == LUA_REFNIL;
+}
+
 int LuaReference::GetLuaType() const
 {
 	this->PushSelf( LUA->L );
diff --git a/stepmania/src/LuaReference.h b/stepmania/src/LuaReference.h
index 427fb8e56c..25f7ba6b29 100644
--- a/stepmania/src/LuaReference.h
+++ b/stepmania/src/LuaReference.h
@@ -25,6 +25,7 @@ public:
 
 	/* Return true if set.  (SetFromNil() counts as being set.) */
 	bool IsSet() const;
+	bool IsNil() const;
 	void Unset() { Unregister(); }
 
 	/* Return the referenced type, or LUA_TNONE if not set. */