json.rs

extern crate serialize;
use serialize::json;
use std::os;
use std::io::fs::File;

fn main() {
    let args: Vec<String> = os::args();

    let mut r = &mut File::open(&Path::new(args[1].as_slice()));

    let json = json::from_reader(r);

    if let Ok(json::Json::Object(map)) = json {
        for key in map.keys() {
            println!("{}", key);
        }
    } else {
        println!("Not an object.");
    }
}