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Date: Mon, 2 Feb 2015 23:14:08 +0400
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To: Robert Stoll <php@tutteli.ch>
Cc: PHP Internals <internals@lists.php.net>, Andrea Faulds <ajf@ajf.me>, 
	Nikita Popov <nikita.ppv@gmail.com>
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Subject: Re: [PHP-DEV] What do we need strict scalar type hints for?
From: dmitry@zend.com (Dmitry Stogov)

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On Mon, Feb 2, 2015 at 9:41 PM, Robert Stoll <php@tutteli.ch> wrote:

> Hi Dimitry,
>
> > -----Urspr=C3=BCngliche Nachricht-----
> > Von: Dmitry Stogov [mailto:dmitry@zend.com]
> > Gesendet: Montag, 2. Februar 2015 10:13
> > An: PHP Internals; Andrea Faulds; Nikita Popov
> > Betreff: [PHP-DEV] What do we need strict scalar type hints for?
> >
> > hi,
> >
> > could you please write down few use cases, when strict scalar type hint=
s
> are really useful.
> >
> > Thanks. Dmitry.
>
> I think strict types are beneficial in all those places where you would
> put manual tests to ensure that the passed value is of a certain type and
> only of this type - removing the hassle (ok, I did not add anything to th=
e
> discussion so far ^^). Right now, I mainly think of functions which expec=
t
> an int - especially in the domain of time and money.  I would expect an i=
nt
> and I would not want that a float can be passed without warning and get
> silently converted to an int (loosing precision in the domain of time or
> money can be crucial).
>
However, IMO it is not necessary to have a strict mode as presented by
> Andrea -- I think it would be good enough if we use the same widening rul=
es
> as in Java, C# etc. and be strict otherwise. I am aware of that with the
> support of BigInteger we would have a widening problem (BigInteger to
> float) but could be solved by a BigDecimal as in Clojure.
>
> Ah... I now something I would definitely want to be strict. I guess a
> typical bug, which is made by many beginners, is using the result of strp=
os
> in an if statement without using the identity operator -- btw. would the
> strict mode affect operators and control structures as well?


no. now we speak only about parameter and return value type hints.


> Would somehow be the logical consequence but I suppose the impact on
> performance would be too big. Or wouldn't it?
>

it wouldn't reduce performance. may be even increase, but it'll break every
second app.


> Back to the topic, if I expect a bool as parameter I would definitely not
> want it to be automatically converted since this is a sink for bugs.
>

I'm not sure. If we would work on a type-safe language I would definitely
agree, but PHP is a "loosely typed language" by definition.

Thanks. Dmitry.


>
> Hope that helps.
>
> Cheers,
> Robert
>
>
>
>
>
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