[RFC][List/Assoc\unique]

2 years ago by Ilija Tovilo — view source — reply

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Hi everyone

After the discussion on adding a new ARRAY_UNIQUE_IDENTICAL flag has
revealed that most would prefer a new function I've decided to create
an RFC for this.

https://wiki.php.net/rfc/list_assoc_unique

This RFC proposes adding two new functions, List\unique() and
Assoc\unique() as alternatives using strict equality (===) semantics,
the former discarding and the latter preserving keys.

Let me know what you think.

Regards,
Ilija

Side note: I really hope the discussion will be about more than just
the namespaces.

2 years ago by tim@bastelstu.be — view source — reply

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https://wiki.php.net/rfc/list_assoc_unique

This RFC proposes adding two new functions, List\unique() and
Assoc\unique() as alternatives using strict equality (===) semantics,
the former discarding and the latter preserving keys.

I believe this would be better solved as part of the more generic
"expanded iterable helper functions" proposal (which I really hope makes
it into a proper RFC that is accepted):

https://externals.io/message/118896

Deduplication is reasonably well-defined for arbitrary iterators (even
infinite iterators) and I don't think iterators (esp. Generators) should
remain second-class citizens to arrays going forward.

Side note: I really hope the discussion will be about more than just
the namespaces.

In addition to the reasons above: Yes, adding two new single-function
namespaces IMO is not a good thing, because it only adds to the
inconsistency. Adding new namespaces should be part of a "bigger picture".

Best regards
Tim Düsterhus

2 years ago by me@jhdxr.com — view source — reply

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Hi Ilija,

Thanks for the RFC. In general, I like the idea but there are certain things not clear to me.

What will happen if we pass a list to Assoc\unique?

Assoc\unique([1, 2, 3, 1]);

What will happen if the array (no matter list or assoc) contains pure value and reference which are strict equal? As the RFC says "references are preserved."

$a = 1;
$arr1 = [$a, &$a];
$arr2 = [&$a, $a];
List\unique($arr1);
List\unique($arr2);

Currently the RFC (proposal section, function signature) claims the parameter are bool type, which is obvious wrong. But this is just a minor mistake, what I really want to ask here is do we support array only or any array like input?

Side note: I really hope the discussion will be about more than just the namespaces.

Adding two new namespaces with single function doesn't look good to me, especially I cannot think of anything that we may add to these two namespace in the future.

Regards,
CHU Zhaowei