private void ResolveSuperExpression(SuperExpression expr)
{
if (_currentClass == ClassType.None)
{
Error(expr.Keyword, "cannot use 'super' outside a class");
}
else if (_currentClass != ClassType.SubClass)
{
Error(expr.Keyword, "cannot use 'super' in a class with no superclass.");
}
ResolveLocal(expr, expr.Keyword);
}
private object EvaluateSuperExpression(SuperExpression expr)
{
int distance = _locals[expr];
LoxClass superclass = (LoxClass)_environment.GetAt(distance, new Token(TokenType.Super, "super", null, 0));
LoxInstance obj = (LoxInstance)_environment.GetAt(distance - 1, new Token(TokenType.This, "this", null, 0));
var method = superclass.FindMethod(expr.Method.Lexeme);
if (method == null)
{
throw new RuntimeError(expr.Method, $"Undefine property {expr.Method.Lexeme}");
}
return(method.Bind(obj));
}