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References: <173d2736435.eeebc066559719.6668730031195302987@manuelcanga.dev> <DM6PR07MB66189348DC25742658121507F9470@DM6PR07MB6618.namprd07.prod.outlook.com>
In-Reply-To: <DM6PR07MB66189348DC25742658121507F9470@DM6PR07MB6618.namprd07.prod.outlook.com>
Date: Sun, 9 Aug 2020 11:58:41 -0300
Message-ID: <CAEsg9X0L525jE7hxwPXBJBZwuVPUyvtZuVLBhXi4xFdTL-=sDA@mail.gmail.com>
To: tyson andre <tysonandre775@hotmail.com>
Cc: Manuel Canga <php@manuelcanga.dev>, Internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="00000000000092a33a05ac7313e2"
Subject: Re: [PHP-DEV] [RFC] Import of variables
From: david.proweb@gmail.com (David Rodrigues)

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I suggests to make something like Node does: import "file.php" ($a, $b) so
$a and $b must be extracted from file.php context. All other variables
should be ignored.

Or, to avoid create more complexity and possible new keywords to import
syntax, maybe create a new function:

importx(string $file, ?array $extract = null) and requirex(...) (importx
and requirex is only pseudo)

Em dom, 9 de ago de 2020 11:42, tyson andre <tysonandre775@hotmail.com>
escreveu:

> Hi Internals,
>
> > 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 ).
>
> To be clear: The variables in the top-level scope depend on what has
> require()d/include()d a file.
> The top-level scope starts off as being global, but if a file is required
> from within a function/method/closure (e.g. the autoloader closure), then
> the top-level scope in the require()'d file uses variables (e.g. $this)
> from whatever context called require().
>
> It may be possible to use a declare syntax, e.g.
> declare(used_variables='all') for `'all'`, `null`, `['var1', 'var2']`, etc.
> - Otherwise, you face the issue of where `use vars` should be allowed,
> what happens if there's a statement before `use vars`, etc.
>
> I can see this as having some use cases, such as in configuration files or
> files used for bootstrapping.
> For example,
>
> ```
> <?php
> declare(used_variables=null);
>
> $api_base = IS_PRODUCTION ? 'https://example.com/api/' : '
> http://localhost/api';
> do_stuff();
>
> return [
>     // long config array
>     'url_new' => "$api_base/new",
>     'url_all' => "$api_base/all",
> ];
> ```
>
> This feature (ignoring the question of syntax) would ensure that people
> reading the file knew that $api_base was not modified by other files
> and that other files did not read local variables created within a
> configuration/bootstrapping file in unexpected ways,
> which is a fairly common issue in some web apps I've worked on.
> Opcache would also do a better job at optimizing code if it knew which
> variables in a top-level scope couldn't be modified.
>
> That being said, there's been opposition to extensions to the language
> that add functionality that can be implemented in other ways, as in Rowan's
> comment,
> but peoples opinions depend on the specifics of the proposal
> (e.g. `match` was added and was more performant than chained conditionals
> or switch).
>
> As Rowan said, there are ways to reimplement this:
> - Wrapping the config file or bootstrapping file in a closure, global
> function, or class method
> - `function safe_require_once(string $path, $vars = []) { extract($vars);
> require($path); }` from the caller, to limit what variables are passed in.
> IDEs/tooling would be worse at telling you if a file name had a typo,
> though.
>
> Regards,
> - Tyson
> --
> PHP Internals - PHP Runtime Development Mailing List
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>
>

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