Re: Any interest in a list type?

Miscellaneous thoughts on this: - Working to have a vote on https://github.com/php/php-src/pull/4886 might be a good first step, and something I was personally interested in seeing in 8.0-dev. However, in the event you can't rule out that is_array($listParam) might not return true in the final implementation you decide on, maybe wait. (you said it'd be a subtype, and it seems like a lot of code would break, so that seems unlikely) - How would array_shift(), array_merge(array, list), array_intersect, etc., preg_match(), etc be handled? Would they return lists or arrays? - I'd really have liked to see data structures such as sets, variable-length vectors, etc. in core natively available as objects (or other types, but objects seemed the most practical). Right now, there's php-ds https://www.php.net/manual/en/book.ds.php , but if I wanted to use vec/list in an application/library that was used in a wide variety of places, I'd really rather have something in core. (the drawbacks of using a polyfill would outweigh the performance benefits for a small fraction of adopters) - If those data types were natively available, maybe opcache and/or the jit could use specialized opcodes to reduce the overhead of offsetGet, etc., if the class was known. - References to list iyped properties class X { public list $list; } $x->list = &$localVar; unset($localVar[1]); may cause problems in implementation details if they're a subtype of arrays. Forbidding them in typed properties and limiting the type to params and return types may work. - Having them limited to param type and return type checks (including some internal global function return types) would be how I'd prefer it (instead of adding a separate type elsewhere) PHP already has special handling for iterable/callable. - Future scope of a list type hint might be to add a deprecation notice for list ($x, $y) = $array or `foreach ($x as list($y)) to avoid confusion (even though it's currently unambiguous, and that probably will remain unambiguous) - Tyson