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Date: Mon, 25 Apr 2016 11:46:03 +0300
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Subject: Re: [PHP-DEV] [RFC] PHP Attributes
From: dmitry@zend.com (Dmitry Stogov)



On 04/24/2016 07:57 PM, Levi Morrison wrote:
> On Sun, Apr 24, 2016 at 10:03 AM, Dan Ackroyd <danack@basereality.com> wrote:
>> On 21 April 2016 at 22:13, Dmitry Stogov <dmitry@zend.com> wrote:
>>> Hi,
>>>
>>>
>>> I would like to present an RFC proposing support for native annotation.
>>>
>> Hi Dmitry,
>>
>> Although everyone will have an opinion about the syntax, I think there
>> is one criticism that should be thought about; the chosen syntax isn't
>> future expandable to other concerns.
>>
>> People have talked about "design by contract" RFCs where annotation
>> like data is readable by the engine. The current proposed syntax
>> _could_ be used to store DBC data, but it would not be clear what
>> would be annotation data to read by the application, and what was DBC
>> data to be read by the engine.
>>
>> Changing the proposed syntax to be something like @attr(...) would
>> allow it to be expanded in the future by adding a @contract(...)
>> construct:
>>
>> @attr(test($a + $b > 0))   // This is attribute data read by userland code
>> @contract(require($a + $b > 0, 'InvalidFooArgsException'))  // This is
>> DBC data read by the engine.
>> function foo($a, $b) {
>>      ...
>> }
>>
>> Making features be compatible with future features would avoid a lot
>> of potential pain down the road.
> Genuine question[1]: how is @attr() different than `<<attr()>>`? Also,
> isn't `@attr()` 100% valid user-land code today that can precede
> function or constant declarations?
@attr() - is a valid "silenced" call to function named "attr".
This syntax can't be reused.

Thanks. Dmitry.


>
>    [1] I don't like that I have to make that explicit but it is what it is.