Re: [RFC] Import of variables

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 > To unsubscribe, visit: https://www.php.net/unsub.php > >