> On Mar 14, 2022, at 3:20 PM, Lynn <kja...@gmail.com> wrote: > > On Mon, Mar 14, 2022 at 8:04 PM Mike Schinkel <m...@newclarity.net > <mailto:m...@newclarity.net>> wrote: > > Variable variables provide functionality[1] that if removed would force major > rewrites of PHP applications that were architected in a way that depends on > that functionality. > And while probably between 90% and 99% of the time when someone uses variable > variables there are better alternatives, variable variables make certain code > possible that would be impossible without them.
> Do you have examples where this is the case? Most of these things cannot be done without the functionality provided by variable variables. However a few are examples could be handled differently but would require significant rewrite to fix without a new get_value_from_variable_name() function. Either way, these are just from the first few pages of those 162.2k results on SourceGraph.com <http://sourcegroup.com/>: https://github.com/microsoft/sql-server-samples/blob/master/samples/development-frameworks/laravel/vendor/jeremeamia/SuperClosure/src/SerializableClosure.php#L200-L208 <https://github.com/microsoft/sql-server-samples/blob/master/samples/development-frameworks/laravel/vendor/jeremeamia/SuperClosure/src/SerializableClosure.php#L200-L208> https://github.com/mockery/mockery/blob/master/library/Mockery/Generator/StringManipulation/Pass/MethodDefinitionPass.php#L151 <https://github.com/mockery/mockery/blob/master/library/Mockery/Generator/StringManipulation/Pass/MethodDefinitionPass.php#L151> https://github.com/vlucas/phpdotenv/blob/master/tests/Dotenv/DotenvTest.php#L251 <https://github.com/vlucas/phpdotenv/blob/master/tests/Dotenv/DotenvTest.php#L251> https://github.com/squizlabs/PHP_CodeSniffer/blob/master/src/Standards/PSR12/Tests/Classes/ClassInstantiationUnitTest.inc#L34-L38 <https://github.com/squizlabs/PHP_CodeSniffer/blob/master/src/Standards/PSR12/Tests/Classes/ClassInstantiationUnitTest.inc#L34-L384> https://github.com/kanaka/mal/blob/master/impls/php/interop.php#L19 <https://github.com/kanaka/mal/blob/master/impls/php/interop.php#L19> https://github.com/moodle/moodle/blob/master/mod/data/tests/lib_test.php#L1293 <https://github.com/moodle/moodle/blob/master/mod/data/tests/lib_test.php#L1293> https://github.com/moodle/moodle/blob/master/mod/data/tests/generator_test.php?L105#L104 <https://github.com/moodle/moodle/blob/master/mod/data/tests/generator_test.php?L105#L104> https://github.com/FriendsOfPHP/PHP-CS-Fixer/blob/master/tests/Fixer/FunctionNotation/StaticLambdaFixerTest.php#L236 <https://github.com/FriendsOfPHP/PHP-CS-Fixer/blob/master/tests/Fixer/FunctionNotation/StaticLambdaFixerTest.php#L236> https://github.com/phpipam/phpipam/blob/master/functions/PEAR/Net/Ping.php#L284 <https://github.com/phpipam/phpipam/blob/master/functions/PEAR/Net/Ping.php#L284> https://github.com/api-platform/core/blob/main/src/Core/Annotation/ApiProperty.php#L154-L159 <https://github.com/api-platform/core/blob/main/src/Core/Annotation/ApiProperty.php#L154-L159> https://github.com/wp-cli/wp-cli/blob/master/php/WP_CLI/Runner.php#L1285-L1287 <https://github.com/wp-cli/wp-cli/blob/master/php/WP_CLI/Runner.php#L1285-L1287> https://github.com/phpmyadmin/phpmyadmin/blob/master/libraries/classes/Database/Qbe.php#L878-L879 <https://github.com/phpmyadmin/phpmyadmin/blob/master/libraries/classes/Database/Qbe.php#L878-L879> https://github.com/PrestaShop/PrestaShop/blob/develop/classes/SpecificPrice.php#L474 <https://github.com/PrestaShop/PrestaShop/blob/develop/classes/SpecificPrice.php#L474> > Using arrays is a compatible replacement as far as I know, and I highly doubt > these kinds of hacks are necessary. "Necessary" is a judgement call. If you never do meta-programming in PHP then these _techniques_ — calling them "hacks" is a bit incendiary — would not ever seem necessary. However if a developer does work on projects that by-requirement leverage meta-programming then variable variables are a tool in one's toolkit that one would be hobbled without. An area where I have seen them required is in theming where the CMS or plugin vendor wants to make it easier on the themer by creating dynamically-named variables in scope and then including a PHP file intended to be used as a template, and the in other functions being able to access those dynamically-named variables. Other areas are in developer tools written in PHP for PHP developers. That said, are you objecting to the "variable variable" syntax, or more broadly to the ability to access the value of a variable given its name (as a new function could provide)? -Mike P.S. BTW, I agree that if a developer can avoid variable variables there would be doing themselves and future maintainers a big favor. I am only commenting because in rare cases variable variables provide a capability that you cannot achieved another way. But if PHP provides that other way by way of a function then the only concern is BC breakage for those who have used the technique.
