Rust definitely seems cool as a no-compromises systems language. Why is Mozilla developing it, though? What is the intended use? Supposedly it will be used by Firefox, but for what? Rendering? JavaScript compilation?
The browser engine in question is called Servo, and initial discussions of its design have only just recently begun. See more here: http://smallcultfollowing.com/babysteps/blog/2012/03/28/serv...
Well, per the FAQ: (https://github.com/mozilla/rust/wiki/Doc-project-FAQ)
What is this project's goal, in one sentence?
To design and implement a safe, concurrent, practical, static systems language.One is the belief that it would be to good to write everything in assembly (from OSs to browsers to games) so that it would be faster. See they heard that assembly is faster and lower-level, so "the more the merrier, right"?
Another (that you don't get much nowadays, but there was a time in the early 90's that was very common) was this fascination with Ada. Mostly because of all the marketing and BS articles at the time. The reasoning here was "well, if they use that for missiles and F16s, it must be the best, right?"
They could even make use of Ada's real time capabilities. It was a pleasure when I ran QNX (2005) and everything responded to my actions on spot, even their browser (Voyager). Today I run FF and after a while and with several tabs open it takes (many) seconds until this beast shows some reaction.
BTW I don't use Ada but mostly Haskell since 2001.
None of this require buying into marketing hype.
It's bad because the language is large and some parts feel out of date, the memory management is more complicated than it ought to be, and compilers are thin on the ground and often expensive. Targeting C at a new machine is much easier than Ada, and this is probably the main reason why it lost.
What was meant half-joking (that they should use Ada for the browser) becomes better the more I think about it. When I look at Rust's design goals, I find that Ada 2012 fulfills them (at least superficially). Additionally: if users have to learn Rust as a new language, then they can use Ada anyway (which has a good track record, while there's no experience with Rust's possible quirks). And I guess if they ask AdaCore to include certain features as add-ons to their GNAT compiler, they'd do it or assist (because for fun and for the publicity that Firefox uses Ada).
edit: most complains seem to come from strong typing and static type checking.
DARPA funds lots of computer science research, so I doubt academic dislike of DOD is a big factor.
While I can't say that I completely understand the underlying concepts, I believe that this is the sort of thing that Rust's typestate mechanism is intended to achieve (the way I seem to understand it, it's sort of like design-by-contract, except invariants may be checked at dozens of places per line rather than just at function boundaries). You should look into it if Ada's safety guarantees excite you.
> Are you going to use this to suddenly rewrite the browser and change everything? Is the Mozilla Corporation trying to force the community to use a new language?
> No. The Mozilla Corporation's involvement is at the labs level: the group concerned with doing experiments. The point is to explore ideas. There is currently no plan to incorporate any Rust-based technology into Firefox.
You're right that it would be idiotic to spend the money and time to develop this if they didn't intend to use it in their products, but they've gone out of their way to make people understand that the Rust they can see today is not going to be shoved down their throats. Whether some eventual successor Rust that may or may not resemble the one we have today is used for some kind of rewrite is probably a foregone conclusion, but they clearly don't want us deciding whether to support or object based on what exists today.
I sound like I'm making a big deal out of a minor distinction, but I don't like seeing what I saw on Slashdot, which was essentially, A) Rust devs announce Rust 0.1, B) someone submits story to Slashdot saying Mozilla is forcing everyone to abandon C++ and switch to Rust in the near future, C) everyone on Slashdot complains that Rust isn't going to perform and ought to have language features X, Y, Z. This cycle misinformation/non-information is going to persist as long as we emphasize the foregone conclusion that this might be used in some kind of far-distant rewrite ahead of the actual news, which is just that 0.2 of Rust, an experimental language, came out today.