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Date: Mon, 16 Feb 2015 23:00:42 +0100
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To: francois@php.net
Cc: Arvids Godjuks <arvids.godjuks@gmail.com>, Jefferson Gonzalez <jgmdev@gmail.com>, 
	Rowan Collins <rowan.collins@gmail.com>, PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Reviving scalar type hints
From: pajousek@gmail.com (=?UTF-8?Q?Pavel_Kou=C5=99il?=)

On Mon, Feb 16, 2015 at 9:50 PM, Fran=C3=A7ois Laupretre <francois@php.net>=
 wrote:
>> De : Pavel Kouril [mailto:pajousek@gmail.com]
>>
>> Hello,
>>
>> I know this is probably a pretty unpopular opinion in PHP (based on
>> the replies I got in the other thread), but different values for
>> parameters should be IMHO solved by method overloading and such.
>
> The question is not that it's unpopular, it's that 1. It requires strict =
types, and 2. If we want to solve this by polymorphism, we must also suppor=
t polymorphism on functions. Now, tell me how you would solve the tan(int|f=
loat) case with polymorphism ? One 'tan' function for int, one for float ? =
str_replace(string|array, string|array, string|array, int &) is also a nice=
 case to study if you can't sleep...
>
> Sorry but polymorphism on scalar types is possible with strict types only=
, which is out of scope for the next RFC.
>
> Fran=C3=A7ois
>

I will get to this more tomorrow, but now just a short notes:

I'd only have tan(float) with int being able to be passed and the
value would be implicitly converted to float. This is something even
strongly typed languages normally do, and there is no reason PHP
shouldn't be able to. If somebody would make a tan(float) and tan(int)
declarations, then when calling tan($x), the apropriate one based on
current type of $x should be called. I don't see any reason why this
can be done only for strongly typed languages; could you name exact
reasons?

The str_replace(string|array $search, string|array $replace,
string|array $subject[, int &$count ]) is a harder one to comment on
though. I will refrain from answering on that one right now and will
get back to that one tomorrow, because that one needs a little bit
more thinking.

Regards
Pavel Kouril