On 25 August 2024 21:00:03 BST, Bilge <bi...@scriptfusion.com> wrote:
>class Suspension {
> /**
> * @param int $delay Specifies the delay in milliseconds.
> */
> public function suspend(int $delay = 1_000) {
> var_dump($delay);
> }
>}
>
>class MySuspension extends Suspension {
> /**
> * @param float|int|null $delay Specifies the delay in seconds.
> */
> public function suspend(float|int|null $delay = null) {
> parent::suspend((int)(($delay ?? 0) * 1000) ?: default);
> }
>}
>
>new MySuspension()->suspend(2.2345); // int(2234)
>
>Not only have I demonstrated the need to use multiplication or division to
>change the scale, but also the need to cast.
Possibly something got lost as you redrafted the example, because as you've
written it, neither the multiplication nor the cast are applied to the value
looked up by "default". The parameter reduces to "(expression) ?: default",
which I've already agreed is useful.
I was thinking about why "bitwise or" feels so different from other operators
here, and I realised it's because it's idempotent (I hope I'm using that term
correctly): if the specified bits are already set, it will have no effect.
Consequently, we know that ($x | SOME_FLAG) & SOME_FLAG === SOME_FLAG without
knowing the value of $x. That in turn means that regardless of how the default
value changes in future, we know what "default | JSON_PRETTY_PRINT" will do.
It's as though each bit flag is a separate parameter, and you're saying "pass
true to $prettyPrint, but let the implementation decide sensible defaults for
all other flags".
The majority of operators don't have that property, so they require some
additional assumptions about the default, which might not hold in future. For
instance, if you use "default + 1", you are implicitly assuming that the
default value is not the maximum allowed value.
Rowan Tommins
[IMSoP]
