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Date: Thu, 15 Jan 2015 14:51:18 +0000
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 Leigh <leight@gmail.com>,
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To: Zeev Suraski <zeev@zend.com>
Subject: Re: [PHP-DEV] [RFC] Scalar Type Hints v0.2
From: ajf@ajf.me (Andrea Faulds)

Hi Zeev,

> On 15 Jan 2015, at 14:32, Zeev Suraski <zeev@zend.com> wrote:
>=20
>> Whether or not they are in the majority, a very large portion of PHP
>> developers would prefer strict typing. In particular, the most vocal =
ones
>> would seem to. There are also a lot of PHP developers who would =
prefer
>> weak typing. Thus we have a problem: either approach to scalar hints =
will
>> upset a large portion of the community.
>=20
> That's correct.  As I said though, the source of the opposition is
> fundamentally different.
> The camp which opposes weak typing opposes it based on the idea that =
it
> doesn't behave in the way that would suit their needs.
> The camp which opposes strict typing - which incidentally includes =
most of
> the people who originally created the language - opposes it based on =
the
> assertion that it goes against the spirit of the language.  That is =
equally
> true for the v0.2 proposal you've just submitted.

I=E2=80=99m not really sure this is true. I agree that strict types =
aren=E2=80=99t entirely in keeping with the =E2=80=9CPHP way=E2=80=9D. =
However, there are plenty of people who are against them not for that =
reason, but simply because they don=E2=80=99t work well for them. Plus, =
I=E2=80=99m not sure strict typing causes as much of a problem if it is =
off by default. Nobody is forced to use it, the language would stay =
beginner-friendly and weakly-typed. Indeed, strict type hints don=E2=80=99=
t stop PHP being weakly-typed. They just check types at function call =
boundaries. Think of it as a sanity check.

>=20
>>> How do you deduce that 'nobody uses them' from the fact that some
>>> group of people said they won't?  I'm sorry, but it makes no sense,
>>> especially given the positive feedback you saw on internals, making =
it
>>> clear that there would be in fact people using it.
>>=20
>> Not all of it was positive. Sure, a lot of people would use them =
though,
>> but
>> I=E2=80=99ve heard quite a few developers say they wouldn=E2=80=99t =
use them and continue
>> to use manual (!is_int($foo))-style assertions.
>=20
> Of course not all of it was positive, but it was overwhelmingly =
positive.
> Very few opposed.  Someone saying they won't use it doesn't count as
> opposition.

Let=E2=80=99s have a look. =46rom a quick skim over the thread for v0.1:

* In favour of weak types (or the RFC anyway): Adam, Stas, yourself, =
Jordi, Pierre,
* Against, in favour of strict types: Maxime, Nikita, Markus, Marco, =
Leigh, Levi, Sven(?)
* In favour of strict types, not against weak types as compromise: =
Matthew
* Somewhat in favour: Sebastian
* In favour of allowing both approaches: Marcio, Thomas, Marco

I apologise if I am misrepresenting anyone=E2=80=99s position.

This is unlikely to be super-representative of the PHP community. =
However, I=E2=80=99m not sure I=E2=80=99d say =E2=80=9Coverwhelmingly =
positive=E2=80=9D. It can be easy to get confirmation bias when reading =
RFC threads.

It is very clear to me that a lot of people would like strict types, and =
some people would like weak types. As to their relative numbers, I =
cannot say.

I don=E2=80=99t think it=E2=80=99s really fair to cover only the use =
case of one half of the PHP community. The other half counts too. This =
is a rather divisive issue.

>  You see, PHP exists for 15-20 years now.  There aren't any
> must-have features that aren't in it.  No single feature we add will =
be used
> by everyone, and people telling us they won't use this feature =
shouldn't
> 'deter' us in any way.

I don=E2=80=99t think this is true: if we are making a feature less =
useful (and therefore making many people avoid it), it=E2=80=99s worth =
considering if that is a problem. If we can easily cover the vast =
majority of people=E2=80=99s use cases, rather than catering to only one =
group of people (who may or may not be the majority), why don=E2=80=99t =
we?

>=20
>>> If there's one thing that's worse than introducing an alien concept
>>> like strict typing into PHP, it's introducing it as a feature that
>>> will include all the negatives of this alien concept, PLUS have the
>>> ability to radically change how it behaves based on a runtime =
option.
>>=20
>> This isn=E2=80=99t a runtime option, it is entirely compile-time. =
Much like
>> namespaces
>> are not a runtime option. There isn=E2=80=99t even the ability to =
toggle it at
>> runtime,
>> unless we somehow add some ability to edit the flags on individual
>> opcodes.
>=20
> Compile time and runtime in PHP are intertwined when you factor in
> cross-file interaction.

Except that is not the case for this proposal, which explicitly and =
deliberately prevents the directive affecting inclusion. The behaviour =
is impossible to toggle at runtime, unless you=E2=80=99re using some =
weird extension which lets you edit the flag on the ZEND_DO_FCALL =
opcode.

Thanks!

--
Andrea Faulds
http://ajf.me/