Re: [RFC] Scalar Type Hinting With Casts (re-opening)

Hello again, One of the issues with the RFC as it stands is how to handle bool casting. While int, float and string only allow lossless casting (with the exception of objects, but we can’t really do anything about that), bool’s behaviour at the moment is quite different. I don’t think it makes sense so I won’t discuss the current behaviour, only possible new ones. One option is simply to forget about being lossless and make the bool type hint accept any value, meaning any truthy value or any falsey value would yield what is expected without error. This would ensure that if some stupid programmer (like myself ;) has passed in a non-boolean truthy/falsey value to your function, it’ll be handled correctly. It would mean all your bit hacks ($foo & FLAG etc.) would work, anything you got from $_GET (e.g. ?foobar=1). However, this is unlikely to catch bugs in code, because literally any PHP value would work. For that reason, I’m not sure this is the way forward. Another option is go completely strict and allow only boolean values, failing everything else. This would be unlike the int, float and string hints, which are flexible and cast, but would be more helpful for catching bugs. However, not casting at all isn’t very “PHP-like”, and forcing people to manually cast with (bool) might not be ideal. If we were to go for this one, I might also accept objects casting to bool (which the default handler does), because I don’t want to stop extension developers from making bool-like objects if they so please. The final option I’m thinking about is a limited set of values. TRUE, FALSE and NULL would be accepted, along with the integer and float values 1 and 0 (which are the int/float TRUE and FALSE cast to, respectively), ‘1’ and the empty string (which are the string values TRUE and FALSE cast to), and ‘0’ (which (string)(int)FALSE would give you), along with objects casting to boolean. It’s not a perfect solution, but I currently feel that this is the most sensible option bar going for full strictness. I’m not really decided, however. Every time I try to think about this, I usually end up going in circles. Anthony doesn’t seem to be decided either. Hence I’m putting this up for discussion. What are your thoughts? -- Andrea Faulds http://ajf.me/