Hi,
On jeudi 9 juin 2022 18:46:53 CEST Marco Pivetta wrote:
> ## nesting these functions within each other
>
> What happens when/if we nest these functions? Take this minimal example:
>
> ```php
> $a = 'hello world';
>
> (fn () {
> (fn () {
> echo $a;
> })();
> })();
> ```
Capture bubbles up. When an inner function uses a variable, the outer function
in fact uses it too, so it's captured by both functions, by-value.
This example prints "hello world": The inner function captures $a from the
outer function, which captures $a from its declaring scope.
This is equivalent to
```php
(function () use ($a) {
(function () use ($a) {
echo $a;
})();
})();
```
> ## capturing `$this`
>
> In the past (also present), I had to type `static fn () => ...` or `static
> function () { ...` all over the place, to avoid implicitly binding `$this`
> to a closure, causing hidden memory leaks.
>
> Assuming following:
>
> * these new closures could capture `$this` automatically, once detected
> * these new closures can optimize away unnecessary variables that aren't
> captured
>
> Would that allow us to get rid of `static fn () {` declarations, when
> creating one of these closures in an instance method context?
It would be great to get rid of this, but ideally this would apply to Arrow
Functions and Anonymous Functions as well. This could be a separate RFC.
--
Arnaud Le Blanc
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