There one thing that really stirred my interest: nil isn’t allowed If this really is what I think it is (a certain reference to a class can never be nil) then

There one thing that really stirred my interest: nil isn’t allowed If this really is what I think it is (a certain reference to a class can never be nil) then I am really excited. It never made sense to me that someone was able to call a function I wrote that really needed instances with nils instead, so I was forced to check and throw in case they did. It's just not clear and it leads to a lot of unnecessary checking or nil pointer exceptions.