> On Dec 17, 2020, at 4:11 PM, Saif Eddin Gmati <azj...@protonmail.com> wrote:
>
> Hello Aaron,
>
> First, I want to say that I love this proposal and would love to see it land
> in the next PHP release, but I have one question regarding this:
>
>
>> Promises result in the “What color is your function” problem as described in
>> the introduction of the RFC. Returning promises from functions means that
>> functions calling those functions must also return promises, resulting in
>> the entire call stack needing to return promises.
>
> Hack-Lang provides `HH\Asio\join` function which allows awaiting Awaitables
> in sync code, so you are capable of running multiple async tasks concurrently
> without having to declare the entire call stack as "async" or with an
> "Awaitable" return type, isn't this possible?
>
> ```
> use namespace HH\Asio;
>
> async function async_task(): Awaitable<void> {
> await Asio\usleep(1000000);
> }
>
> <<__EntryPoint>>
> function main(): void {
> $start = microtime(true);
>
> $async = async {
> concurrent {
> await async_task();
> await async_task();
> };
>
> return 'hello';
> };
>
> $result = Asio\join($async);
>
> printf('Result: %s ( %f )', $result, microtime(true) - $start); // output
> "Result: hello ( 1.010382 )"
> }
>
> ```
>
> Regards,
>
> Saif.
>
Hi Saif,
`HH\Asio\join()` implements a synchronous await (I don't know the details of
how its implemented, possibly involving entering and exiting the built-in event
loop), but it does not solve the problem that functions using `await` need to
be declared using `async` and return an Awaitable. Your example declares
`async_task()` as async, while a similar function using the proposed fiber API
would not need to change the function declaration to use `Fiber::suspend()`.
There's an example in the RFC using `Amp\delay()` that is very similar to your
code sample.
Fibers allow existing interfaces to be implemented using either sync or async
I/O because the interface does not need to change to return promises/awaitables.
Cheers,
Aaron Piotrowski
--
PHP Internals - PHP Runtime Development Mailing List
To unsubscribe, visit: https://www.php.net/unsub.php
