add helpers

stepmania/src/LuaManager.cpp

@@ -673,30 +673,28 @@ bool LuaHelpers::RunScriptFile( const RString &sFile )
 }
 
 
-bool LuaHelpers::RunScript( Lua *L, const RString &sScript, const RString &sName, RString &sError, int iArgs, int iReturnValues )
+bool LuaHelpers::LoadScript( Lua *L, const RString &sScript, const RString &sName, RString &sError )
 {
-	lua_pushcfunction( L, GetLuaStack );
-	int iErrFunc = lua_gettop( L );
-
 	// load string
-	{
 	int ret = luaL_loadbuffer( L, sScript.data(), sScript.size(), sName );
 	if( ret )
 	{
 		LuaHelpers::Pop( L, sError );
-			lua_pop( L, iArgs );
-			lua_remove( L, iErrFunc );
-			for( int i = 0; i < iReturnValues; ++i )
-				lua_pushnil( L );
 		return false;
 	}
-	}
 
-	// move the function above the params
+	return true;
-	lua_insert( L, lua_gettop(L) - iArgs );
+}
+
+bool LuaHelpers::RunScriptOnStack( Lua *L, RString &sError, int iArgs, int iReturnValues )
+{
+	lua_pushcfunction( L, GetLuaStack );
+
+	// move the error function above the function and params
+	int iErrFunc = lua_gettop(L) - iArgs - 1;
+	lua_insert( L, iErrFunc );
 
 	// evaluate
-	{
 	int ret = lua_pcall( L, iArgs, iReturnValues, iErrFunc );
 	if( ret )
 	{
@@ -706,12 +704,27 @@ bool LuaHelpers::RunScript( Lua *L, const RString &sScript, const RString &sName
 			lua_pushnil( L );
 		return false;
 	}
-	}
 
 	lua_remove( L, iErrFunc );
 	return true;
 }
 
+bool LuaHelpers::RunScript( Lua *L, const RString &sScript, const RString &sName, RString &sError, int iArgs, int iReturnValues )
+{
+	if( !LoadScript(L, sScript, sName, sError) )
+	{
+		lua_pop( L, iArgs );
+		for( int i = 0; i < iReturnValues; ++i )
+			lua_pushnil( L );
+		return false;
+	}
+
+	// move the function above the params
+	lua_insert( L, lua_gettop(L) - iArgs );
+
+	return LuaHelpers::RunScriptOnStack( L, sError, iArgs, iReturnValues );
+}
+
 bool LuaHelpers::RunExpression( Lua *L, const RString &sExpression, const RString &sName )
 {
 	RString sError;

stepmania/src/LuaManager.h

@@ -49,9 +49,19 @@ private:
 
 namespace LuaHelpers
 {
-	/* Run a script with the given name.  The given number of return values are left on
+	/* Load the given script with the given name.  On success, the resulting
+	 * chunk will be on the stack.  On error, the error is stored in sError
+	 * and the stack is unchanged. */
+	bool LoadScript( Lua *L, const RString &sScript, const RString &sName, RString &sError );
+
+	/* Run the function with arguments at the top of the stack, with the given
+	 * number of arguments.  The specified number of return values are left on
 	 * the Lua stack.  On error, nils are left on the stack, sError is set and 
 	 * false is returned. */
+	bool RunScriptOnStack( Lua *L, RString &sError, int iArgs = 0, int iReturnValues = 0 );
+
+	/* LoadScript the given script, and RunScriptOnStack it.  iArgs arguments are
+	 * at the top of the stack. */
 	bool RunScript( Lua *L, const RString &sScript, const RString &sName, RString &sError, int iArgs = 0, int iReturnValues = 0 );
 
 	/* Run the given expression, returning a single value, and leave the return value on the