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Date: Wed, 4 Sep 2019 09:21:54 +0200
Message-ID: <CANS-=pco95mG_6AmZhFYJ-ig8UEagZoR-MZ65AVEAm9foDZdhg@mail.gmail.com>
To: =?UTF-8?Q?Micha=C5=82_Brzuchalski?= <michal.brzuchalski@gmail.com>
Cc: Fwentish Aelondes <fwentish@gmail.com>, PHP Internals List <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Silent Types
From: kjarli@gmail.com (Lynn)

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Hi,

Would this warrant a having mixed types? By making every variable of type
"mixed" when no type is defined, regardless of what value it receives or is
initialized with, this would make an opt-in system. This behavior would
cater developers who prefer only strict types, only dynamic types, and
those that want to type their code bit by bit without putting declares that
affect whole files.

```
$foo =3D 'foo';
// same as
mixed $oneHundred =3D 100;
// difference being:
// $foo is accepted when 'string' is typed in the signature
// $oneHundred is accepted when 'int' is typed in the signature

// no longer mixed, only accepts their defined type as value
// and is accepted only as their defined type in signatures
string $foo =3D 'foo';
int $oneHundred =3D 100;

// does imply we might need custom type definitions in the future to not
have to work with mixed
typedef Stringable =3D string | MyToStringInterface;
Stringable $foo =3D (bool) rand(0, 1) ? 'foo' : new MyStringableObject('foo=
');
```

Note that this behavior would require making some decisions whether or not
in the future this opt-in behavior should change when a default value is
given, such as with C# and type inference when declaring a variable, based
on its assigned value.

Regards,
Lynn van der Berg

On Wed, Sep 4, 2019 at 8:12 AM Micha=C5=82 Brzuchalski <
michal.brzuchalski@gmail.com> wrote:

> =C5=9Br., 4 wrz 2019, 05:52 u=C5=BCytkownik Fwentish Aelondes <fwentish@g=
mail.com>
> napisa=C5=82:
>
> > Hello internals,
> >
> > Zeev's idea to bring peace to the galaxy seems like a good idea, but
> > impossible to implement in practice.
> >
> > But it got me thinking about how one might introduce static typing
> > into a dynamically typed language w/out breaking BC.
> >
> > And then I had this crazy idea:
> >
> > //int
> > $i =3D 0;
> >
> > //string
> > $c =3D 'c';
> >
> > //float
> > $pi =3D 3.14;
> >
> > If static typing in php was *only* an opt-in kind-of-thing, would this
> > work? Could the parser be built to identify 3 or 4 different keywords
> > in comments and give warnings or fatal errors for type conversions of
> > variables that have the type specified in the immediately preceding
> > comment?
> >
> > Just a (crazy) idea.
> >
> > ---- Fwentish
>
>
> IMO it's crazy idea and we should not change the way comments work
> especially inline comments which even aren't kept in opcache.
>
> I think better approach would be to put type in front of first variable
> declaration like:
>
> [type] $variable =3D $value;
>
>
> BR,
> --
> Micha=C5=82 Brzuchalski
>

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