Cleanup: change RunExpression to a RunScript helper. Never tack on

"return "; the caller can do that if it wants.  Instead, just act as a helper to
display a generic dialog on error.

stepmania/src/LuaManager.cpp

@@ -313,12 +313,12 @@ bool LuaManager::RunScript( const CString &sScript, const CString &sName, CStrin
 }
 
 
-bool LuaManager::RunExpression( const CString &sExpression )
+bool LuaManager::RunScript( const CString &sExpression, const CString &sName )
 {
 	CString sError;
-	if( !RunScript( "return " + sExpression, "in", sError, 1 ) )
+	if( !RunScript( sExpression, sName.size()? sName:"in", sError, 1 ) )
 	{
-		sError = ssprintf( "Lua runtime error parsing \"%s\": %s", sExpression.c_str(), sError.c_str() );
+		sError = ssprintf( "Lua runtime error parsing \"%s\": %s", sName.size()? sName.c_str():sExpression.c_str(), sError.c_str() );
 		Dialog::OK( sError, "LUA_ERROR" );
 		return false;
 	}
@@ -328,7 +328,7 @@ bool LuaManager::RunExpression( const CString &sExpression )
 
 bool LuaManager::RunExpressionB( const CString &str )
 {
-	if( !RunExpression( str ) )
+	if( !RunScript( "return " + str ) )
 		return false;
 
 	/* Don't accept a function as a return value. */
@@ -343,7 +343,7 @@ bool LuaManager::RunExpressionB( const CString &str )
 
 float LuaManager::RunExpressionF( const CString &str )
 {
-	if( !RunExpression( str ) )
+	if( !RunScript( "return " + str ) )
 		return 0;
 
 	/* Don't accept a function as a return value. */
@@ -363,7 +363,7 @@ int LuaManager::RunExpressionI( const CString &str )
 
 bool LuaManager::RunExpressionS( const CString &str, CString &sOut )
 {
-	if( !RunExpression( str ) )
+	if( !RunScript( "return " + str ) )
 		return false;
 
 	/* Don't accept a function as a return value. */

stepmania/src/LuaManager.h

@@ -24,9 +24,14 @@ public:
 	/* Reset the environment, freeing any globals left over by previously executed scripts. */
 	void ResetState();
 
-	/* Run a complete script in the global environment, which returns no value. */
+	/* Run a script with the given name.  Return values are left on the Lua stack.
+	 * Returns false on error, with sError set*/
 	bool RunScript( const CString &sScript, const CString &sName, CString &sError, int iReturnValues = 0 );
 
+	/* Convenience: run a script with one return value, displaying an error on failure.
+	 * The return value is left on the Lua stack. */
+	bool RunScript( const CString &sExpression, const CString &sName = "" );
+
 	/* Run an expression in the global environment, returning the given type. */
 	bool RunExpressionB( const CString &str );
 	float RunExpressionF( const CString &str );
@@ -60,8 +65,6 @@ public:
 	/* Read the table at the top of the stack back into a vector. */
 	static void ReadArrayFromTable( vector<bool> &aOut, lua_State *L = NULL );
 
-	/* Run an expression.  The result is left on the Lua stack. */
-	bool RunExpression( const CString &sExpression );
 	lua_State *L;
 };
 

stepmania/src/LuaReference.cpp

@@ -113,13 +113,17 @@ void LuaReference::ReRegister()
 
 void LuaExpression::SetFromExpression( const CString &sExpression )
 {
-	m_sExpression = sExpression;
+	m_sExpression = "return " + sExpression;
 	Register();
 }
 
 void LuaExpression::Register()
 {
-	LUA->RunExpression( m_sExpression );
+	if( !LUA->RunScript( m_sExpression ) )
+	{
+		this->SetFromNil();
+		return;
+	}
 
 	/* Store the result. */
 	this->SetFromStack();