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To: rowan.collins@gmail.com, bobwei9@hotmail.com
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Date: Sun,  5 Jun 2016 10:15:18 +0200 (CEST)
Subject: Re: [PHP-DEV] [RFC] [PRE-VOTE] Union types
From: mails@thomasbley.de ("Thomas Bley")

maybe you can add a few examples to the type table in the rfc, so everybody knows how it actually works:

function test(int | float | string $a) {var_dump($a);}
test(42.0); // float(42)
test('42'); // string(2) "42"

function test2(int $a) {var_dump($a);}
test2(42.0); // int(42)
test2('42'); // int(42)

function test3(int|bool $a) {var_dump($a);}
test3('foo'); // true

Regards
Thomas


Bob Weinand wrote on 03.06.2016 14:30:

> 
>> Am 3.6.2016 um 14:18 schrieb Rowan Collins <rowan.collins@gmail.com>:
>> 
>> On 03/06/2016 12:59, Bob Weinand wrote:
>>>> function l(string | float $x) { echo gettype($x); }
>>>> l("1.5a"); // I would expect string, but float would succeed if attempted
>>> 
>>> Exact matches *ALWAYS* match without coercion.
>> 
>> Gah, I keep making that mistake in my examples. I did say I was struggling to
>> get my head around things! ;)
>> 
>> I'm still missing an explanation of exactly where you derived the current
>> proposed rules from, though. The RFC just states "these rules are not an
>> invention of this proposal", but goes on to say "applies PHP casting rules in
>> a sane way", which implies some decisions were involved in drawing up these
>> rules.
>> 
>> I think you may be right that the rules are as simple as they can be, and I
>> don't want to waste too much of your time, but a basic summary of the
>> reasoning used would be much appreciated.
>> 
>> Regards,
>> -- 
>> Rowan Collins
>> [IMSoP]
> 
> The *weak casting* rules (i.e. what gets converted how and what can be
> converted to the other type) are not an invention of the proposal.
> 
> The proposal however defines the specific order.
> 
> I’ve added a reasoning why not left-to-right now. As this seemed to be asked
> multiple times.
> 
> Also, the specific reasoning why I propose that specific order the rules are
> in:
>> Otherwise PHP's casting rules are applied in an order to be as lossless as
>> possible.
> 
> That’s really the only motivation behind that.
> 
> Bob
> 
> 
> 
> 
>