On Wed, Jul 9, 2025, at 10:42 AM, Eric Norris wrote: >> An init hook would be clearer, certainly, though it also has its own edge >> cases. Can you set something that has an init hook? What happens if >> there's both a get and init hook? These probably have answers that could be >> sorted out, but that's a different question from "why the <censored> does a >> readonly class forbid me using even rudimentary hooks???" >> >> I'd be open to a follow up RFC for an init hook, though I likely wouldn't >> write it myself. But that's a different topic than what we're addressing >> here. >> >> --Larry Garfield > > I'm not entirely sure I follow - it sounds like your email states that > `readonly` should be interpreted as `writeonce`, which makes sense, > but then why would an `init` hook not be the appropriate answer here? > > The two scenarios you listed (`set` hooks for validation and lazy > computed properties) seem like they could be solved by allowing `set` > hooks (everyone seems +1 to that), an `init` hook, and disallowing > `get` hooks. It would sidestep the controversial nature of a `get` > hook for the property. > > It feels to me like an init hook would be the more conservative > approach, and would (I imagine) still allow for potential `readonly` > engine optimizations like Tim pointed out. Once we allow `get` hooks, > there's no going back. If we still needed to add `get` hooks in the > future, it's not off the table. > > I don't know that I feel strongly here, but there does seem something > intuitively off with allowing a get hook for a readonly (writeonce) > property.
Can an init hook reference itself, the way get and set can? If there is both an init and set hook, what happens? Is it different if set reads from itself than if it writes to itself? Should combining init and set be forbidden as confusing? Can you have both an init hook and a get hook? What happens then? Repeat all of the above on readonly properties. I don't know the answer to any of those. We could probably collectively figure out some answers to that in time, but that's a much larger lift than either Nick or I have any interest in engaging in at this point, especially when there is a reasonable solution right in front of us that is trivial to implement. --Larry Garfield
