Like I said, this is a boiled-down example of the essence of the problem. Yes, the hashmap mangle is an example, and the option map, and similar standard container methods, and quite a few similar functions in my own specific container classes (contrary to popular opinion, in non-trivial projects people do end up writing their own specialized containers...). In general the problem is "I am a container, give me a function to modify some piece of me" combined with an invoker that says "do the following to modify some piece of the container, accessing and updating all sort of variables". It is a pretty significant use case, which seems to have nothing to do with RAII, and bugs me a lot in my code.
On Sat, Nov 30, 2013 at 11:57 PM, Patrick Walton <pcwal...@mozilla.com>wrote: > On 11/30/13 1:54 PM, Oren Ben-Kiki wrote: > >> There were several threads about this, >> https://mail.mozilla.org/pipermail/rust-dev/2013-October/006105.html for >> example. I don't see how that code can be converted to RAII at all. Sure >> it can be done with cells, or possibly with tuples (though, well, doing >> this _manually_? <<shudder>>). It really just begs for >> stack-allocated-once-closures. >> > > Well, the functions `attempt_1` and `attempt_2` in that message don't do > anything, so there isn't anything to convert. Do you have other specific > common examples of functions that can't be converted to RAII? > > `mangle` is one. `Option::map` and friends are another. Are there others? > > Patrick > >
_______________________________________________ Rust-dev mailing list Rust-dev@mozilla.org https://mail.mozilla.org/listinfo/rust-dev
