2020-07-11 16:50 GMT, Rowan Tommins <rowan.coll...@gmail.com>: > On 11 July 2020 16:13:24 BST, "Olle Härstedt" <olleharst...@gmail.com> > wrote: >>Yes, the point is to be limiting. :) Just like with immutability, you >>apply certain limitations to avoid access abuse. > > > Taken to extremes, this is the "secure a server by encasing it in concrete" > strategy - the hard part about designing useful limitations is not the parts > you want to make impossible, it's the parts you want to remain easy. > > There is a reason Rust has a whole set of mechanisms for managing ownership, > not just a single "mine/yours" split, because they allow the programmer to > express what they want to do with the object. > > >>Regarding "freezing" an object, I actually already wrote about this in >>a blog post, using dependency injection as a use-case, and a trait to >>add a method to check the refcount: >>http://olleharstedt.github.io/php/2020/07/08/immutable-at-borrow.html > > > The difference in my mind between freezing an object and tracking ownership > is that "frozen/unfrozen" would be an explicit state set on the object, not > a measurement that differs as it is used. So either the user says "freeze > $object", and it is then immutable for the rest of the program, or some > point after construction implicitly freezes it with the same effect. > > This eliminates the dependence on tracking ownership or giving meaning to > the refcount, because no matter how you received the object, you must no > longer cause it to be mutated. > > It also has much lower performance impact. Even the automatic form can > probably be performed by the compiler - e.g. if "new" was called in this > function, insert a call to "freeze" before the first time the object appears > as a function parameter > > Regards, > > -- > Rowan Tommins > [IMSoP] > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: https://www.php.net/unsub.php
OK, but then there's no need for any compiler changes - just make trait CanBeFrozenTrait, add a property $isFrozen : bool, and then make sure all methods check this property and throw an exception if it's violated. -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: https://www.php.net/unsub.php
