Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:111387
Date: Sun, 09 Aug 2020 11:01:28 +0200
To: "Internals" <internals@lists.php.net>
Message-ID: <173d2736435.eeebc066559719.6668730031195302987@manuelcanga.dev>
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Subject: [RFC] Import of variables
From: php@manuelcanga.dev (Manuel Canga)

Hi Internals,

I'd like to open up a discussion around the implementation of a new
functionality: 'import of variables'.

This functionality would allow to create a new  'use vars' keyword in order to can use( or cannot use )  global variables in local scope( of current file ).

I think the best is a example:

```php
<?php

$a = 1;
$b = 2;
$c = 3;

include __DIR__.'/without_import.php';
include __DIR__.'/all_import.php';
include __DIR__.'/none_import.php';
include __DIR__.'/some_vars.php';
include __DIR__.'/global_in_function.php';
```

## without_import.php

```php
<?php

echo $a; //1
echo $b; //2
$c = 'any value'; //replace value in global var
```

## all import.php

```php
<?php

use vars all;

echo $a; //1
echo $b; //2
$c = 'other value'; //replace value in global var
```

## none_import.php

```php
<?php

use vars none;

echo $a; //Warning: undefined var $a
echo $b; //Warning: undefined var $b
$c = 'other value'; //assign value to local var
```


## some_vars.php

```php
<?php

use vars $a, $c, $d; //Warning: undefined var $d

echo $a; //1
echo $b; //Warning: undefined var $b
$c = 'a value'; //replace value in global var
```

## global_in_function.php

```php
<?php

use vars $a, $c;


function hello() {
	global $a, $b, $c;

	echo $a; //1
	echo $b; //null.
	$c = 'end value'; //replace value in global var
}

hello();
```


In a project with a lot of global vars( like WordPress ) this functionality avoids conflicts and easy replacements of values in main global vars.


Regards
--
Manuel Canga