Hi, On 5 April 2016 at 12:06, Michał Brzuchalski <mic...@brzuchalski.com> wrote:
> Hi Marco, > > Ad. 1 it is posiible to redeclare in a sub-class final property as > non-final, here is some gist presenting my current impl working like: > https://gist.github.com/brzuchal/12ebda1efed59440a78ba43bff116728 > Does this work for public properties as well? > Ad. 2. `final` means class variable (like static) or class instance > property can not change their reference, it is impossible to replace zval > in such property, in my opinion `immutable` is object behavior when using > some methods you receive newly created (cloned) object which is changed > exactly like `DateTimeImmutable` > http://php.net/manual/en/datetimeimmutable.add.php > I am aware of what `final` means in other languages, it just seems that everyone then needs to translate back and forth from `final` to `immutable`. In addition to that, `final` has different meaning in inheritance (re-used keyword), so this adds to the confusion for people unfamiliar with the feature. > Ad. 3 it would be awesome if there could be final variables in general, it > would be quite stable if no one could change your variable, AFAIK zvals > have IMMUTABLE flag which could be used, don't know it for sure I'm rather > PHP dev than C there would be need some internals guru to ask if it's > posiible. > > P.S. We've meet on PHPCon'15 in Poland, thanks for +1. > YW! > > Cheers, > -- > Michał Brzuchalski (aka brzuchal) > > 2016-04-05 11:13 GMT+02:00 Marco Pivetta <ocram...@gmail.com>: > >> Hi Michał, >> >> First of all: +1 to this: very useful for value objects! >> >> A few questions: >> >> * can you re-declare a final property in a sub-class, making it >> therefore non-final? (I have reasons to do that, related with altering >> states via mappers) >> * do we want to use `final`, or `immutable` for these properties? >> `final` seems to just be a confusing term here. >> * is this feature portable to variables in general? I realize that >> adding metadata to ZVals has huge performance implications, but it would be >> interesting to do that for performance improvements further down the line >> >> Cheers, >> >> >> Marco Pivetta >> >> http://twitter.com/Ocramius >> >> http://ocramius.github.com/ >> >> On 4 April 2016 at 19:53, Michał Brzuchalski <mic...@brzuchalski.com> >> wrote: >> >>> Hey Internals, >>> >>> I'm new here. I've been wondering / working on adding final properties >>> into >>> PHP lang. >>> >>> This work started once I had the time to read the "Core Java for >>> Impateient" by Cay S. Horstmann >>> and found it very usefull to have final properties like Java. >>> >>> Those properties differ than `const` because they can be set at runtime - >>> but only once in their lifetime. >>> Such properties could be very usefull in Singletons, ValueObjects etc. >>> impl >>> like: >>> >>> class Money { >>> public final $amount; >>> public final $currency; >>> public function __constructor($amount, $currency) { >>> $this->amount = $amount; >>> $this->currency = $currency; >>> } >>> } >>> >>> In above example there is even no need for getter because those >>> properties >>> are immutable through >>> the final keyword, it means those properties cannot change their >>> references >>> just like in Java >>> https://en.wikipedia.org/wiki/Final_(Java) >>> >>> I've already started some impl on own fork >>> https://github.com/php/php-src/compare/master...brzuchal:final-properties >>> I've got some basics in C programming, don't know yet if I can impl it >>> complex. >>> >>> I was wondering if it is usefull in yours opinion or is it only my >>> impression. >>> >>> I can provide an RFC if it sounds usefull and if I get Wiki karma >>> >>> Thanks >>> -- >>> Michał Brzuchalski (aka brzuchal) >>> >> >> > As an additional question: how will this (eventually) play with typed properties? I am aware that you cannot declare a class named `final`, but that may change in future, so better factor it into any possible outcomes of the RFC. Cheers, Marco Pivetta http://twitter.com/Ocramius http://ocramius.github.com/
