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Well, that's really bad, because I think that things should be implemented in the best way possible. "Nobody used them", yeah, probably because no other languag

Well, that's really bad, because I think that things should be implemented in the best way possible. "Nobody used them", yeah, probably because no other language (apart from CL) had it, so nobody knew how to leverage them. But leave it in place and at some point in future time, some blogger would write a nice article on using them in Rust and developers would catch up in this cool feature. I develop in Common Lisp and conditions&restarts are so much superior to the other error handling paradigms i've seen, that it's not fun being left without them.

steveklabnik 9y ago
At the time, those docs were the error handling documentation, so people did know they existed. They still weren't used anyway.
- alien_at_work 9y ago
  I think the point is that sometimes showing documentation that something exists isn't enough for everyone to "get it". Sometimes you need some kind of technology evangelist to show something really cool they did with a feature for the creative process to begin on a larger scale. Out of curiousity, if this was just a macro and no one was using it, what would have been the harm in just leaving them in? Is this a part of the language that changes so much it made maintainance a pain?
  - steveklabnik 9y ago
    Macros in Rust are global, insta-stable, and have no namespacing. This means any macro we put in std means you cannot define a macro in any Rust program with that same name. This is one of the reasons we've been working on a new macro system, to fix these kinds of issues. "Just leave it in" isn't a good justification for a feature. We'd then require that every implementation of Rust ever, forever, implements this too. Being in std is a high bar. Beyond that, there are a host of other reasons: https://github.com/rust-lang/rust/commit/454882dcb7fdb03867d695a88335e2d2c8f7561a https://github.com/rust-lang/rust/commit/454882dcb7fdb03867d...
draegtun 9y ago
Perl6 & Smalltalk also have them (conditions&restarts). And i've seen modules to add condition systems to perl5, Ruby & Clojure. But these are kinda of hacks so the more languages that have it baked-in the better!
- flavio81 9y ago
  Thanks, I stand corrected. It seems Perl has everything!

steveklabnik 9y ago

At the time, those docs were the error handling documentation, so people did know they existed. They still weren't used anyway.

alien_at_work 9y ago
I think the point is that sometimes showing documentation that something exists isn't enough for everyone to "get it". Sometimes you need some kind of technology evangelist to show something really cool they did with a feature for the creative process to begin on a larger scale. Out of curiousity, if this was just a macro and no one was using it, what would have been the harm in just leaving them in? Is this a part of the language that changes so much it made maintainance a pain?
- steveklabnik 9y ago
  Macros in Rust are global, insta-stable, and have no namespacing. This means any macro we put in std means you cannot define a macro in any Rust program with that same name. This is one of the reasons we've been working on a new macro system, to fix these kinds of issues. "Just leave it in" isn't a good justification for a feature. We'd then require that every implementation of Rust ever, forever, implements this too. Being in std is a high bar. Beyond that, there are a host of other reasons: https://github.com/rust-lang/rust/commit/454882dcb7fdb03867d695a88335e2d2c8f7561a https://github.com/rust-lang/rust/commit/454882dcb7fdb03867d...

draegtun 9y ago

Perl6 & Smalltalk also have them (conditions&restarts). And i've seen modules to add condition systems to perl5, Ruby & Clojure. But these are kinda of hacks so the more languages that have it baked-in the better!

flavio81 9y ago
Thanks, I stand corrected. It seems Perl has everything!