Rust front-end to GCC

[Philip Herron <redbrain at gcc dot gnu dot org>]

Hey all

Some of you may have noticed the gccrs branch on the git mirror. Since
PyCon IE 2013 i gave a talk on my Python Front-end pet project and
heard about rust by a few people and i never really looked at it
before until then but i've kind of been hooked since.

So to learn the language i've been writing this front-end to GCC. Only
really a a month or  so on and off work in between work. Currently it
compiles alot of rust already in fairly little effort on my side GCC
is doing loads of the heavy lifting.

Currently it compiles most of the basic stuff such as a struct an impl
block while loop, functions expressions calling methods passing
arguments etc. Currently focusing on getting the typing working
correctly to support & and ~ and look at how templates might work as
well as need to implement break and return.

There is still a lot of work but i would really like to share it and
see what people think. Personally i think rust will target GCC very
well and be a good addition (if / when it works). I really want to try
and give back to this community who have been very good to me in
learning over the last few years with GSOC.

To get a jist of what i am compiling in my tests are something like:

fn fib1 (n:int) -> int {
    if (n <= 1) { 1 }
    else { n * fib1 (n - 1) }
}

fn fib2 (n:int) -> int {
    let mut i = 1;
    let mut result = 1;
    while (i <= n) {
        result = result * i;
        i = i + 1;
    }
    result
}

fn main () {
    fib1 (10);
    fib2 (10);
}

Or

struct mytype {
    x : int
}

impl mytype {
    fn test (self) -> int {
        println ("yyoyoyo");
        test2 (1)
    }
}

fn main () {
    let x = mytype { x : 1 };
    let z = x.x;
    let y = x.test ();
    let a = test2 (y);
}

fn test2 (x : int) -> int {
    let z = x;
    1 + z
}

Theses are both pretty abstract test cases but were the ones i just
made work a while ago. Lots more work to do on it but i feel these 2
test cases working is kind of a mile stone for me.

I will start a wiki page on the project and the code i work on is at
http://gcc.gnu.org/git/?p=gcc.git;a=shortlog;h=refs/heads/gccrs and i
have it on github first mostly for travis CI and so i can do a bunch
of commits and rebase etc http://github.com/redbrain/gccrs

Thanks

--Phil