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Date: Tue, 15 Jul 2014 18:32:32 +0100
Cc: Stas Malyshev <smalyshev@sugarcrm.com>,
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To: Rowan Collins <rowan.collins@gmail.com>
Subject: Re: [PHP-DEV] [RFC] Scalar Type Hinting With Casts (re-opening)
From: ajf@ajf.me (Andrea Faulds)


On 15 Jul 2014, at 18:24, Rowan Collins <rowan.collins@gmail.com> wrote:

> Stas Malyshev wrote (on 15/07/2014):
>> IMO, having consistent rules is much more, orders of magnitude more
>> important than serving any particular use case
>=20
> We are adding a new feature to a language which is already =
inconsistent. We can only make it consistent with one part of the =
language by making it inconsistent with another.
>=20
> If we take consistency as such a priority that we create a feature =
that is not actually useful, we will have wasted our effort, and made =
the language worse, not better. Saying "who cares if its useful, as long =
as it matches some other part of the language" is a very poor argument =
IMO.
>=20
> That's an extreme, and I'm not saying anyone is saying precisely that, =
but I am getting rather weary of the back-and-forth over what is =
"consistent", rather than thinking about what we want to achieve, and =
what is the best way to achieve that.

I=92d argue it=92s better to do the right thing here, which is easier, =
and then do the right thing in the other place later, which is harder, =
than it is to do the wrong thing now because the other place also does =
the wrong thing. Having saner implicit casting for scalar type hints =
will be easier than changing the behaviour of zend_parse_parameters.

>> What you want is strict typing then.
>=20
> No, I want to introduce the notion of a "lossless cast", allowing =
things like (int)'123' to be valid. This distinction has been explained =
many times.
>
>> And if() working the same way -
>> after all, if function can be unaware of the flag, if() is definitely
>> unaware of it.
>=20
> Not necessarily. An if() statement is clearly and unambiguously =
working with boolean values. Anyone looking at if( $foo & BIT_FLAG ) can =
know, based on basic knowledge of the language, that an implicit cast is =
taking place.
>=20
> Someone looking at my_super_function( $foo & BIT_FLAG ) cannot know =
whether that parameter is being interpreted as a boolean or is actually =
being measured against that same BIT_FLAG (or some other integer =
operation) without consulting the source code (or, at least, trusting =
the documentation).
>=20
>> I am not among them. If you want
>> to enforce code style, we already have tools for that, but I don't =
think
>> this particular one should be in the language.
>=20
> The logical conclusion from that is not to have type hints at all. So =
far, that is in fact the only consensus the PHP community has ever =
reached - not to have scalar type hints. (I don't mean that you =
necessarily hold that position, but it is the logical conclusion of that =
particular line of reasoning.)
>=20
> Regards,
> Rowan Collins
> --=20
> [IMSoP]
>=20
> --=20
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>=20

I, myself, generally agree with all this, though I=92m not sure quite =
whether Anthony does at the moment.
--
Andrea Faulds
http://ajf.me/