Hi Rob,
Am 3. September 2025 22:44:58 MESZ schrieb Rob Landers <rob@bottled.codes>:
>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 think what we actually would need is an EnumSet which can be used with any
enum but (based on its ordinal) but this would play nicely together with
generics `new EnumSet<JsonOption>`.
>
>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
Marc
