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To: "Anthony Ferrara" <ircmaxell@gmail.com>
Cc: "PHP internals" <internals@lists.php.net>, "Nikita Popov"
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Date: Mon, 21 Jan 2013 20:46:12 +0100
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Subject: Re: [PHP-DEV] [VOTE] Alternative typehinting syntax for accessors
From: glopes@nebm.ist.utl.pt ("Gustavo Lopes")

On Mon, 21 Jan 2013 20:28:12 +0100, Anthony Ferrara <ircmaxell@gmail.com>  
wrote:

> Gustavo
>
> I've voted "No" due to concerns I mentioned in most part in IRC, but  
> which
>> I think should be here on the record. So my voting statement:
>>
>> I'm voting against this proposal because I think the proposed syntax
>> strongly suggests that the property is bound to a specific type. This  
>> has
>> several problems:
>>
>> * It's a promise that's not guaranteed. As long as the getter is allowed
>> to reference the value of the variable can arbitrarily be changed to
>> whatever type. It may also be possible to do the same with  
>> unserialization.
>>
>
> This is pretty easily solved by removing the ability to return a  
> reference from the getter when the shortcut syntax is used. In fact,  
> remove the
> ability to set the body of a getter at all (it would only allow you to
> specify the visibility. If you need references, you can't use this  
> syntax...

So now we have a new non-obvious special case for when a specific syntax  
is used. So much for the equivalence argument. Allowing no getter body has  
its own problems btw (lazy instantiation is no longer possible for  
instance).

In any case, you leave unanswered other scenarios. Unserialization (and  
remember there are various unserialization implementations)? Bug in the  
setter (though I'm sure we could remove the ability to set the body as  
well)? Now what's your solution? PHP should start policing the type of the  
properties in all those scenarios? Maybe we should introduce Error  
exceptions for those runtime field type mismatches, like the JVM does.

>> * The benefits are minimal. The only real benefit is cutting maybe two
>> lines of code in an indisputably common scenario.
>>
>
> Cutting two lines of code per instance. And considering that this is used
> all the time, that can add up to some pretty significant (if not trivial)
> boilerplate that's removed...
>

OK, so we disagree on the social value of removing, let's say 20 lines of  
boilerplate.

But you still left unanswered my other concerns about the fact this  
actually transmits the idea that PHP will enforce the type of a variable.  
You may think that's not an issue; even then, I think this is a very  
important change that merits more discussion. It's interesting that you  
claim we "need a vision", but actually we could be about to start  
introducing a fundamental change in the language in an incremental  
backdoor fashion.

-- 
Gustavo Lopes