What if #:authentic (or whatever) were only allowed on immutable objects and we allowed them to be copied? Then contracts could protect them.
Robby On Thu, May 11, 2017 at 5:38 PM, Matthias Felleisen <[email protected]> wrote: > > @ Christos > > #:authentic explicitly introduces a channel of communication that it is not > protectable by contracts. This makes Racket’s contract system explicitly > incomplete. It might have been incomplete in the past for other reasons. > > If the name isn’t fixed, #:no-proxy-allowed would be my preference. > > — Matthias > > > > > >> On May 11, 2017, at 12:48 PM, Scott Moore <[email protected]> wrote: >> >>> I agree that generally don't want performance declarations that >>> interfere with reasonable interposition. The good uses of `#:authentic` >>> would be in places where the struct representation of a value is not >>> exposed or where the values themselves are not exposed (so any >>> interposition means being on the "inside" where you can change the >>> code, anyway). >> >> Yes, I agree with this. I think as far as how this changes Racket’s data >> abstraction model, the key is “where the values themselves are not exposed.” >> #:authentic only has an interesting effect in the other case, where >> “outside” code gets its hands on a value of the struct type. Previously, I >> could write a program that used inspectors to impersonate this value >> regardless of the “inside” code’s intent. Now that would no longer be >> possible. >> >> I doubt there is much code that currently relies on being able to do this >> and so I would say go ahead. (Perhaps DrRacket or other debugging tools?) >> >> On the other hand, Spencer already asked if this would be something the >> optimization coach would recommend. I think it would be important for the >> documentation of #:authentic or the implementation of such a coach to stress >> the importance of the rules of thumb you just laid out. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Racket Developers" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/racket-dev/3c430798-e93a-4900-8215-198f77d9b991%40Spark. >> For more options, visit https://groups.google.com/d/optout. > > -- > You received this message because you are subscribed to the Google Groups > "Racket Developers" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-dev/D688771A-C477-40D8-B209-D9506362C5CB%40ccs.neu.edu. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Racket Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-dev/CAL3TdOP%3DRD0EH4E3SQ39jbtks_saC2xW0gNr5VKja42MWFmkXA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
