Promise API

[azjezz]

implement promises according to the Promises/A+ open standard.

[veewee]

Promises sound nice as well, but there are many packages out there already... Does it make a lot of sense to implement it again from scratch (which is a lot of hard work) instead of using amphp or react promises and coroutines? (Which are quite nice and have the async event loops covered through multiple extensions with vanilla PHP callbacks etc.)

[azjezz]

I'm not really sure about this, the question should be: "does it make sense to have promises in a standard library", the issue is we cannot use Amphp, or ReactPHP here, as PSL should not have any dependencies except for PHP itself and core/bundled/external extensions ( we shouldn't rely on PECL extensions as well, see: https://www.php.net/manual/en/extensions.membership.php ). 🤔

[WyriHaximus]

As long as it has a then method we at @reactphp can support it. (Assuming you're wrapping it through our resolve function.)

[azjezz]

I believe guzzle does the same, so I'm closing this as Psl\Result\ResultInterface will have a then method ( see discussion at #65 ), which mean it can act as a promise to some extent.

[veewee]

Wow, that's nice! Did not know react could do that!

[WyriHaximus]

@veewee Yup, only thing is that we assume it is a pure promise with no side effects.