Einar

I do not like this syntax at all and have no problem with user-land solutions.

I see no immediate benefit of the proposed solution over the userland implementations. The RFC mentions a shopping cart example, but I don't think that's cleaner than using league/pipeline or Laravel's pipeline.

It's a bit messy for the simpler examples as well.

It's almost as messy as putting all the functions into each other.

The idea is a nice one, and one that I would welcome, but this proposal puts forward messy syntax that isn't clear!

• Interface shall stay light, pure contracts defining expectations, else they are just abstract classes with multi-inheritance.
• If multi-inheritance is the subject, a specific RFC shall be done on this.
• An other away might be to dig back this RFC to add interface to traits: https://wiki.php.net/rfc/traits-with-interfaces