Warning these are just my impressions, I haven't fully tried out rust.
> 1 - If memory management is a serious problem for the software you work on, I've never found the boost library lacking. This seems like the main selling point for RUST. Given the scope of the project: you guys must be doing something that is so different that it couldn't be rolled into a library - so I'm looking forward to your future posts to see if there is something here that I really am missing out on.
Generally every non-trivial program has bugs(possibly excluding tex which was written by one of the greatest computer scientists of all time and after years of being open with bragging rights for anyone who finds a bug, but I'm not even sure about it). Rust aims to reduce bugs including memory bugs as much as possible with static typing. It's probably the language that most concentrates on preventing bugs with static typing/analysis this side of haskell. Even if c++ could have some similar feature if some library used carefully this is not the same as people could still abuse unsafe features not allowed in rust outside of unsafe blacks.
> 2 - I'm not a fan of the implicitness and I personally don't use 'auto' b/c it makes scanning code harder. I guess this is more of a personal preference.
It is a matter of style but as someone who puts var in front of everything but basic types in c# I think its a good default. An ide can help a lot by showing type on hover.
> 3 - A lot of things are renamed. auto->let, new->box, switch->box You get the feeling that effort was put in to make the language explicitly look different from C++
Although rust is somewhat influenced by C++ aiming to take over its problem domain it is probably more influenced by functional languages like Ocaml. let comes from ocaml, match instead of switch also comes from ocaml(note that match is more powerful then switch). Also note that let isn't exactly the same as auto, let allows declaring local variables, rust default to implicit typing for local variables but you can specify them and it will still have let. ex.
let monster_size: int = 50;
> 4 - the Rust switch statement don't fall through... This one was truly mind blowing. The one useful feature of switch statement got ripped it out! If you don't really need the fall through, I'd just avoid using them completely...
There aren't that many useful switch statements that fallthrough for reasons other then matching multiple values to one execution path and rust allows you to match one of a number of values or in a containing range. ex.
match my_number {
0 => println!("zero"),
1 | 2 => println!("one or two"),
3..10 => println!("three to ten"),
_ => println!("something else")
}
There are some other uses for switch fall through such as duffs device(cool but hard to understand and not necessarily a speed up these days) and things like
http://programmers.stackexchange.com/a/116232 where some cases include other cases(not that common, can be simulated with if/else's). Fallthorugh is a confusing "feature" which can lead to bugs if you forget to put break which goes against the rust philosophy and it would be even more confusing when using the return value of match.(note I'm think this next example is right)
println!("my number is {}!", match my_number {
0 => println!("zero"),
1 | 2 => println!("one or two"),
3..10 => println!("three to ten"),
_ => println!("something else")
}
In rust matches and if/else statemnts are expressions.
This gives you a nice looking ternary expression. And makes some functions shorter.
I think that if there are multiple ';' seperated expressions in an if/else or => result wrapped with {} it will return the last expression if it isn't followed by a ; otherwise it returns unit(a type meaning something similar to void). But I could be wrong.
> 5 - I've never really seen an equivalent to boost (in combination to the STL) in other languages (maybe I didn't look hard enough). Could you maybe make a post about the RUST standard library? Libraries are always the deal breaker
The equivalent of Boost in what way? Boost is a collection of many(>80) different libraries some of which (ab)use the language in very interesting ways. Some of these eventually move into the standard and stdlib. I don't think any other languages have this sort of feeder collection. That said many languages have officially or unofficially blessed libraries which sometimes make it to the stdlib. Rust is fairly young and a moving target so there aren't many 3rd party libraries yet but hopefully that will change once it stabilizes and the package manager is mature.