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Date: Wed, 3 Jan 2018 12:41:19 -0500
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To: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC][DISCUSSION] Strong Typing Syntax
From: tendoaki@gmail.com (Michael Morris)

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On Wed, Jan 3, 2018 at 12:10 PM, Andreas Hennings <andreas@dqxtech.net>
wrote:

> This proposal contains some interesting ideas, which I see as separate:
> 1. A syntax to declare the type of local variables.
> 2. A syntax to declare the type of object properties.
> 3. Preventing local variables, object properties and parameters to
> change their type after initialization/declaration.
>
> For me the point 3 is the most interesting one.
> I think the other points are already discussed elsewhere in some way,
> although they are clearly related to 3.
>
> Point 3 would be a BC break, if we would introduce it for parameters.
> Current behavior: https://3v4l.org/bjaLQ
>
> Local variables and object properties currently cannot be types, so
> point 3 would not be a BC break for them, if we introduce it together
> with 1 and 2.
> But then we would have an inconsistency between parameters and local
> vars / object properties.
>
> What we could do to avoid BC break is to introduce
> declare(fixed_parameter_types=1) in addition to
> declare(strict_types=1).
> For local variables and object properties, the type would always be fixed.
> But for parameters, it would only be fixed if the
> declare(fixed_parameter_types=1) is active.
>
> Maybe to make it less verbose, we could say declare(strict_types=2),
> which would mean the combination of both those things?
> Or some other type of shortcut.
> I think we will have to think about shortcuts like this if we
> introduce more "modes" in the future.
>
>
There will be occasions where having an unfixed variable alongside normal
ones will be desirable.


>
> > Currently the var keyword is used to formally declare a variable.
>
> Are you talking about local variables?
> In which PHP version? https://3v4l.org/o0PFg
>
>
Sorry, I'm confusing PHP for JavaScript. I forgot that the var keyword was
only used in PHP 4 for class members. For some reason my brain assumed it
was usable in a local scope.


> Afaik, currently var is only used for class/object properties from the
> time when people did not declare the visibility as
> public/protected/private.
>
>

>
> If no type is specified, then "mixed" should be assumed, not "scalar".
> Assuming "scalar" would be a BC break, and it would be confusing.
>
>
Ok. I'm misusing the term scalar to mean "variable who's type can be
changed at will depending on context." Sorry.

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