Well, this is not exactly what I want. You can catch exceptions by type, but only from some code (for example, a Java library) that actually throws different ty

Well, this is not exactly what I want. You can catch exceptions by type, but only from some code (for example, a Java library) that actually throws different types of exceptions. In Gosu, I can't throw them by type, at least from what I've seen. I can only throw some generic type of exception (or is it an error? Or something else that implements Throwable? Who knows, Gosu doesn't tell you anything about that) that contains some expression (a String literal), and then anybody who wants to catch it, needs to know that exact expression in order to catch the exception. The more I think about it, the more terrible this looks. I can't even specify to the users of my code which exceptions they should look after (because, it seems, Gosu doesn't allow the throwing of checked exceptions and the 'throws' clause). So if I write some kind of library in Gosu, and if that library is throwing exceptions, I'm basically forcing the users of my library to catch this generic exception (or whatever it is), then put a breakpoint in the catch block and every time something gets caught inspect the expression, hoping that if they test long enough they'll find all of my expressions. Then, they need to write code that covers all the possible cases (a bunch of "if" statements). I sincerely hope that I somehow completely misunderstood what Gosu is trying to do here, because otherwise this is just a terrible solution. That would be a real shame though, because, other than this, I honestly like the language.