Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:111413
Date: Mon, 10 Aug 2020 08:46:19 +0200
To: "Marco Pivetta" <ocramius@gmail.com>
Cc: "Internals" <internals@lists.php.net>
Message-ID: <173d71eb175.11ec80fe0613982.1532514557831836899@manuelcanga.dev>
In-Reply-To: <CADyq6s+gM-tnL7PFo8ryOWSiB3Px2zjAbmbFXETBaJ4m1ThStA@mail.gmail.com>
References: <173d2736435.eeebc066559719.6668730031195302987@manuelcanga.dev> <CADyq6s+gM-tnL7PFo8ryOWSiB3Px2zjAbmbFXETBaJ4m1ThStA@mail.gmail.com>
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Subject: Re: [PHP-DEV] [RFC] Import of variables
From: php@manuelcanga.dev (Manuel Canga)

Hi, Internals,


Thanks, Marco and also to Rowans, Josh, David and Tyson

I'll use IIFE in order to avoid global conflicts.

Regards

 ---- En lun, 10 ago 2020 02:16:06 +0200 Marco Pivetta <ocramius@gmail.com>=
 escribi=C3=B3 ----
 > Hey Manuel,
 >=20
 >=20
 >=20
 >=20
 > On Sun, Aug 9, 2020, 11:02 Manuel Canga <php@manuelcanga.dev> wrote:
 >=20
 > > 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 =3D 1;
 > > $b =3D 2;
 > > $c =3D 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 =3D 'any value'; //replace value in global var
 > > ```
 > >
 > > ## all import.php
 > >
 > > ```php
 > > <?php
 > >
 > > use vars all;
 > >
 > > echo $a; //1
 > > echo $b; //2
 > > $c =3D '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 =3D '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 =3D '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.
 > >         $c =3D 'end value'; //replace value in global var
 > > }
 > >
 > > hello();
 > > ```
 > >
 > >
 > > In a project with a lot of global vars( like WordPress ) this
 > > functionality avoids conflicts and easy replacements of values in main
 > > global vars.
 > >
 >=20
 > This looks like what IIFE do already (you can use them today):
 >=20
 > ```php
 >=20
 > require 'something/with/side/effects.php';
 >=20
 > (static function () use ($a, $b, & $c) : void {
 >     echo $a; //1
 >     echo $b; //Warning: undefined var $b
 >     $c =3D 'a value'; //replace value in global var
 > })();
 > ```
 >=20
 > You can use this right now, and it has the advantage of reporting any
 > missing symbols right at the time at which the closure is declared.
 >=20
 > I tend to use IIFE all the time in procedural code, since they prevent
 > leaking state into globals =F0=9F=91=8D
 >=20
 > >
 >=20