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Date: Mon, 8 Feb 2016 11:53:45 -0600
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Subject: Re: [PHP-DEV] Proposal for a new array function
From: larry@garfieldtech.com (Larry Garfield)

On 2/8/16 11:46 AM, Kinn Julião wrote:
> On Mon, Feb 8, 2016 at 11:38 AM, Rowan Collins <rowan.collins@gmail.com>
> wrote:
>
>> Kinn Julião wrote on 08/02/2016 16:05:
>>
>>> That's the nice thing about userland... you are giving them ability to
>>> implement what they want!
>>> `array_filter([...], 'is_int', ARRAY_FILTER_USE_KEY)` does the job as the
>>> others... don't think having a new function would prevent this.
>>>
>> It does the job, but it is much less efficient in some cases than the
>> foreach and return false case, as it must examine every element; it also
>> has unnecessary memory overhead, creating a filtered list which exists only
>> to be counted and thrown away; and an internal implementation could be
>> optimised even further by exploiting the way the engine stores the array
>> internally.
>>
> How does `array_filter([...], 'is_int', ARRAY_FILTER_USE_KEY)` add that
> *much* overhead?
> And if that's the case, instead of introducing a 99999 array function into
> the core, why not just create a new Object then?
>
> $list = list('foo','bar'); // I know it's a reserved token, don't have time
> to find a better synonym. it's just a sample
> $list[2] = 'baz';
>
> var_dump($list);
>
> string(1) "foo"
> string(1) "bar"
> string(1) "baz"
>
> $list['a'] = 'foobar'; // Fatal error.

I'm confused at the goal here.  Is the intent "I need to do different 
logic if this is a numeric array vs. something else" or "I need to make 
sure this is a numeric array, because things break otherwise"?

If the latter, $foo = array_values($bar); is a reasonably efficient and 
reasonably bulletproof way to ensure you have a strictly numeric array.

>> PHP is at this stage expressive enough that a large number of core
>> functions could be rewritten in multiple ways using other core functions,
>> but that doesn't automatically rule out adding more functions to core where
>> it is useful to do so.
>
> PHP is at a stage where we can add support to a better structure and
> objects support... we don't need a function to check if the keys are
> integer, we need an object that only supports integer as keys, or even a
> generic key...
>
> Would rather have `Map<int, mixed>` than `has_numeric_keys`

Or that.  Which I like even better.  Ahead-of-time typing is much safer 
at scale than runtime typing.  (Of course we then run smack into the 
arrays-and-objects-are-just-different-enough-to-be-annoying problem that 
has plagued us for a decade.)

-- 
--Larry Garfield