On Tue, Mar 23, 2021, at 4:32 AM, G. P. B. wrote: > Greetings internals, > > I'm presenting a new RFC to add support for pure intersection types to PHP. > > An intersection type A&B means that the value must be of type A and of type > B at the same time. > > I'm calling this proposal pure intersection types as there would be no > possibility of mixing intersection and union types, I'm leaving this as a > future scope. > > The current draft is located on GitHub: > https://github.com/Girgias/intersection-types > And the current implementation PR is: > https://github.com/php/php-src/pull/6799 > > Looking forward to the feedback. > > Best regards, > > George P. Banyard
I love this! Thanks, George! A few editorial notes: * Under "Duplicate and redundant types", the prose says "For example, if ''A'' and ''B'' are class aliases, then ''A&B'' remains a legal intersection type". The code sample after it, however, says it's an error. Please clarify. * Under "Adding and removing intersection types", there appears to be some broken code formatting. * The Reflection section still refers to "union" types. I assume that's because that section is still a WIP. * Under "Future Scope / Type Aliases", you refer to "number" as being an alias, but the code sample calls it "CountableIterator". Design notes: * Should we be planning ahead for some future where union and intersection types can be mixed and design the reflection API accordingly? I worry that if we have a ReflectionIntersectionType, and a ReflectionUnionType, that ReflectionIntersectionAndUnionType is just going to make both implementers and users table-flip. --Larry Garfield -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: https://www.php.net/unsub.php
