Re: [RFC] Add is_list(mixed $value): bool to check for list-like arrays

Hi Larry Garfield, > Well, since I'm quoted... :-) > > I'm fine with this, but have one question and one correction: > > * If we do eventually end up with list/vec types, would the naming here conflict at all?  Or > would it cause confusion and name collision?  (Insert name bikeshedding here.) > > * The last quote, from me, has a small error.  The last sentence shouldn't be a bullet > point but its own paragraph, after the list is complete. Yes, there's definitely the potential for naming conflicts if the type is called list but not if it's called vec/vector/varray similar to https://docs.hhvm..com/hack/built-in-types/arrays - I'd prefer the latter if there was a viable implementation. I should note that in the discussion section. If the type is named list instead of vector and ends up incompatible with arrays, there'd need to be an is_list_type($val) or $val is list or some other new type check with a less preferable name. If it's compatible with arrays/lists (e.g. only checked during property assignment, passing in arguments, and returning values), then it wouldn't be an issue. - is_array_list() or is_array_and_list() or is_values_array() would avoid some of that ambiguity but would be much more verbose Providing objects with APIs similar to the external PECL https://www.php.net/manual/en/class.ds-vector.php and the SPL may be easier to adopt because it can be polyfilled, but there's the drawback that there aren't the memory savings from copy-on-write and that there's the performance overhead of method calls to offsetGet(), etc. I'd expect the addition of a separate/incompatible vec type to be a massive undertaking, and possibly unpopular if it splits the language. In Hack/HHVM, it was practical for users to adopt because HHVM is bundled with a typechecker that checks that the uses are correct at compile time - because PHP has no bundled type checker, a new type would potentially cause a lot of unintuitive behaviors. I fixed the formatting of the quote. -- Tyson