On Wed, Jan 22, 2020 at 4:47 PM Nicolas Grekas <nicolas.grekas+...@gmail.com> wrote:
> Hello everyone, > > as announced last week, I'm officially opening a discussion for adding a > "Stringable" interface to PHP 8. > > The RFC and its rationale are presented here as required: > https://wiki.php.net/rfc/stringable > > The patch is found on GitHub, where some discussions happened already, you > might be interested in having a look: > https://github.com/php/php-src/pull/5083 > > TL;DR, I think we need an interface to allow passing objects with a > __toString() method in a type-safe way, using the string|Stringable type. > Here is the stub of the proposal: > interface Stringable { public function __toString(): string; } > > I invite everyone to review the RFC before commenting here as I tried to > sum up considerations that some already had before and that you might have > too. > > Cheers, > Nicolas > I'm wondering whether it could make sense to automatically implement this interface for all classes that define __toString(). Explicitly implementing the interface is useful for the transition period (where old PHP versions also need to be supported), but when considering only PHP 8 support, I think it may make sense to implicitly implement the interface. If the __toString() functionality also works fine without implementing the interface, and there's probably only going to be relatively few consumers of the Stringable type, it will likely be quite common that the interface will not get implemented... Automatically implementing interfaces based on implemented methods could also be a general language feature (see Go interfaces for example), but likely not one we're interested in having in it's full generality. In this particular case, it seems useful though. Regards, Nikita
