> Hi, I worked together with Chris Wright, author of the other RFC covering > the same thing.
Thanks for pointing it out and also thanks CMB for posting the link. I tried to search for this topic but didn't find anything, as we have too many names for this feature. > The most important thing is that we don't want it work like array_merge(); > in other words, it must not cover both lists and maps at the same time. Since PHP array is a mixture of list (traditional array in most of other languages) and map (a k=>v data structure), any new syntax related to PHP array most cover both use cases. `...` means unpacking, I think we are all good with this semantic, the disagreement is about the behavior of key conflict. Let's use your example to start my explanation: ``` ['a' => 1, 'b'=>2, ...['a' => 3]] ``` Since we are create a new syntax with the existing array definition syntax, let's try to do the unpack manually. ``` ['a' => 1, 'b' =>2, 'a' => 3] ``` Although this not a good practice to write such codes, it's still valid in current version without any warning or even notice. The answer for above code is ``` ['a' => 3, 'b' => 2] ``` It looks weird at first glance, but IMO the more important thing is this is how PHP works now. I really don't think it's a good idea to introduce a new way how two arrays will get merged. It will confuse developers. I also notice there is an interesting question in the discussion of your RFC. > So, it's just an operator version of array_merge(), with no advantages > other than brevity? I'm not sure why it's any more or less applicable to > constant arrays vs variables than + or array_merge() are. Yes. The spread operator follows the semantics as `array_merge`, but besides brevity and better performance (no more overhead of function call, and constant array can be compiled at compiled time), this RFC also brings the support for objects implementing `Traversables`. Best regards, CHU Zhaowei -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
