Proof of concept macro to implement LINQ syntax in rust.

linq.rs

macro_rules! query(
    (from $v:ident in $c:ident $(where $mw:expr)* select $ms:expr) => 
        ($c.filter_mapped(|&$v| if(true $(&& $mw)*) { Some($ms) } else { None }))
)

fn main()
{
    let nums = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
    let result1 = query!(from x in nums select x * 2);
    
    let result2 = query!(from x in nums 
                         where x%2 == 0
                         select x * 2);
                         
    let result3 = query!(from x in nums 
                         where x%2 == 0
                         where x%4 == 0
                         select x * 2);
    
    for result1.iter().advance |&num| {
        println(fmt!("%d", num));
    }
    
    println("----");
    
    for result2.iter().advance |&num| {
        println(fmt!("%d", num));
    }
    
    println("----");
    
    for result3.iter().advance |&num| {
        println(fmt!("%d", num));
    }
    
    println("----");
}