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Date: Sun, 5 Nov 2023 14:37:20 +0100
Message-ID: <CAHXoPRuHPvWbDDddxh72MPgH3FT_4PkfW0_Z-8nkHc7eYVTNrw@mail.gmail.com>
To: php internals <internals@lists.php.net>
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Subject: [Discussion] Variable Type Declaration Before Usage
From: oladoyinbov@gmail.com (Oladoyinbo Vincent)

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Hello Internals,

I was wondering if php could introduce this feature or if any experienced C
dev here can work on the implementation of this feature.

Local based variable declaration before usage is available in most
languages like javascript, python, and many more. php has this, but it's
only available while working/dealing with oop related.

There is already an RFC on this:
https://wiki.php.net/rfc/local_variable_types, but it doesn't propose a
good usage syntax to promote readability.

Well, i figured out how this feature syntax could look like:

```

$info: string;
$price: float;
$number: int = 125;
$run: \Closure = fn( string $str ) => $str;

echo $number; // 125

$info = $number; // TypeError
$price = $number; // TypeError
$number = 12.5; // TypeError
$run = "hello world"; // TypeError
```

I was kind of thinking if the declared variables may also affect functions
params:

```php

function priceInfo($price, $info)
{
    return $info . ': $ ' . $price;
}


echo priceInfo(12, 2); // TypeError

echo priceInfo(12.5, 'Price:'); // Price: $12.5

```


So, what is your opinion on this?

Best Regards,
Oladoyinbo Vincent.

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