Hello internals,
I would like to propose a new type of backed enum: flag. This is an
integer-backed enum that requires power-of-two values that can be combined with
the bitwise operators to be used as flags.
In some core functions, it might look like this:
enum JSON_FLAG: flag {
case None = 0;
case ThrowOnError = 0x1 << 1;
// etc.
case PrettyPrint = 0x01 << 4;
// etc.
}
function json_decode(string $data, bool $assoc = false, int $depth = 512,
JSON_FLAG|int $options = JSON_FLAG::None) {}
json_decode($data, options: JSON_FLAG::ThrowOnError | JSON_FLAG::PrettyPrint);
Note that the goal here isn’t so much to save typing space, as it is to provide
easier discoverability through IDEs, better type safety, and better ergonomics
in the language overall.
Attempting to use a backed value that is not a power-of-two would result in a
compilation error. Bitwise operations are performed as though they’re performed
on a regular integer.
What do you think?
I couldn’t find any similar proposals (listed on the RFC page) before proposing
this on the list, so if you’re working on this, please speak up; I’d like to
join forces.
— Rob
