On 11/11/2014 18:01, bearophile wrote:
I agree it's a very important topic (more important/urgent than the GC, also because it reduces the need of the GC). But I think Walter thinks this kind of change introduces too much complexity in D (despite it may eventually become inevitable for D once Rust becomes more popular and programmers get used to that kind of static enforcement).
I think Rust's lifetimes would be a huge change if ported to D. In Rust user types often need annotations as well as function parameters. People tend to want Rust's guarantees without the limitations. I think D does need some kind of scope attribute verification, but we need to throw out some of the guarantees Rust makes to get an appropriate fit for existing D code.
For example, taking a mutable borrowed pointer for a variable means you can't even *read* the original variable whilst the pointer lives. I think no one would try to make D do that, but Rust's reason for adding it is actually memory safety (I don't quite understand it, but it involves iterator invalidation apparently). It's possible their feature can be refined, but basically 'mut' in Rust really means 'unique'.
