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Date: Fri, 18 Sep 2015 02:15:43 +0200
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References: <55FB4791.4040807@gmail.com> <CAOsHV+tE_JCd05K8iTgRoEi40n_ryOJ0E0fqCESae9Vep9F=vw@mail.gmail.com> <55FB533F.7080301@gmail.com>
To: Rowan Collins <rowan.collins@gmail.com>
Subject: Re: [PHP-DEV] Let's discuss enums!
From: bobwei9@hotmail.com (Bob Weinand)

> Am 18.09.2015 um 01:56 schrieb Rowan Collins =
<rowan.collins@gmail.com>:
>=20
> On 18/09/2015 00:16, Marcio Almada wrote:
>> A kitten is working on thathttps://wiki.php.net/rfc/enum. Many points
>> on the linked RFC are compatible to the points you raised so it might
>> be worth reading before even starting any new proposal.
>=20
> Aha, I hadn't seen that, should have thought to search the wiki. =
Still, interesting that we seems to mostly agree on the key decisions, =
although I've gone into more detail about things that he's left as =
Future Scope, which is fair enough.
>=20
> The main thing I'd change if I was writing it is the implicit =
"ordinal" property; I don't really see the point of insisting that the =
order I write "Red, Green, Blue" has some meaning. On the other hand, =
I'd give much more prominence to the name, e.g. by making values() =
return an associative array. You're much more likely to want to say "the =
value whose name is 'RED'" than "the value I defined first in the list", =
IMHO.
>=20
> If you have some kind of initialiser syntax for the values - with or =
without a constructor - you get to have ordinals or explicit values =
(like the Flags example) if you want them, and just names if not:
>=20
> enum RenewalAction{
>    Deny( 0 ),
>    Approve( 1 );
>=20
>    public $ordinal;
> }
> enum Flags{
>    a (1  <<  0),
>    b( 1  <<  1),
>    c(  1  <<  2),
>    d(  1  <<  3 ); public $value; }
>=20
> enum PimaryColours { RED, GREEN, BLUE }
>=20
> Regards,
>=20
> --=20
> Rowan Collins
> [IMSoP]

The reason it is not an associative array is that the names are not =
important.

But we actually need ordinal(), else we'll end up writing =
array_search(TheEnum::values(), $value).
It's mainly important for the purpose of serializing/unserializing =
(manually or internally).

You never should *rely* on the ordinal value of the enum for anything. =
Enums are supposed to be value-less. It's a type. It's not a value. The =
only usage of the value is going external.

Also, I honestly think the Flags example is a bad one. (At least as long =
as we don't have a possibility to typehint combined enums...). If you =
need that, use class constants. They provide exactly what you need.

Bob=