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To: "PHP internals" <internals@lists.php.net>, "Nikita Popov"
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Date: Mon, 21 Jan 2013 19:54:01 +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 19:03:09 +0100, Nikita Popov <nikita.ppv@gmail.com>  
wrote:

> I've opened the vote on the proposal for the alternative accessor
> typehinting syntax:
>
> https://wiki.php.net/rfc/propertygetsetsyntax-alternative-typehinting-syntax#voting
>
> The vote is done under the assumption that the main accessors RFC will
> pass. If it does not, then this proposal is no longer relevant.
>

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.
* The benefits are minimal. The only real benefit is cutting maybe two  
lines of code in an indisputably common scenario.
* The idea of bounding a variable to a type, even if it worked with no  
loop holes, should be examined with much more care than this. We have  
nothing analogous already. It's a misleading argument to say this is just  
a syntactic sugar (technically it is), because it carries a strong  
psychological implication by analogy with other languages like Java. And  
of course, it it had no loopholes, it would mean that we would have gone  
to great lengths to force the property to be of a certain type, and then  
we would not be able to claim it was just a syntactic sugar. So the  
feature is either broken or it's not just syntactic sugar.
* And yes, next we'll start discussing extending this to other variables.  
Yes, this is a slippery slope argument. Slippery slopes are a real  
phenomenon. People interested in this topic can read this reference [1].

[1] https://www.law.ucla.edu/volokh/slippery.pdf

-- 
Gustavo Lopes