Hi Juliette > > Since https://wiki.php.net/rfc/new_in_initializers we can store > > objects in global constants. However, we may not actually read or > > write to the properties of those objects without first fetching the > > constant into a local variable. > > > > const a = new stdClass; > > a->b = 42; // Fatal error: Cannot use temporary expression in write context > > $a = a; > > $a->b = 42; // Works fine > > > > This issue was reported twice, so it seems like this code is generally > > expected to work. > > https://github.com/php/php-src/issues/10497 > > https://github.com/php/php-src/issues/11781 > > > > I have created a patch here to add support for this syntax: > > https://github.com/php/php-src/pull/11788 > > I totally understand that people are trying to do this, but this still > very much feels like scope creep. > > IIRC the new in initializers feature was _intended_ only for enums > (which can't take properties). Now suddenly a "constant" would no longer > be constant... In which case, what's the point of declaring it as a > constant ?
This patch doesn't change the mutability of objects in constants, as they already don't offer interior immutability. https://3v4l.org/s7rHE This is analogous to `const` in JavaScript or `readonly` properties in PHP, where we can't change the value of the variable (or const in this case), but we can modify the properties of the object it's pointing to. I believe the main motivation for `new` in constant expressions was to support nested attributes. Enums have their own mechanism for instantiating cases. Since it was decided to expand the support for `new` to global constants, I would expect it to work with other language constructs, unless there's a good reason for it not to. Ilija -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: https://www.php.net/unsub.php
