remove_iter.rs

use std::ops::DerefMut;
use std::ops::Deref;

#[derive(Show)]
struct List<T> {
    car: T,
    cdr: Option<Box<List<T>>>,
}


fn main() {
    let mut head = Box::new(List {car: 0i8, cdr: None});
    for i in range(1, 42i8) {
        head = Box::new(List {car: i, cdr: Some(head)})
    }

    {
        let delete = 8;
        let mut now = head.deref_mut();
        loop {
            let mut temp = now;
            if temp.cdr.is_none() {break};
            if temp.cdr.as_mut().unwrap().car == delete {
                let x = temp.cdr.take();
                temp.cdr = x.unwrap().cdr;
                break
            }
            now = temp.cdr.as_mut().unwrap().deref_mut();
        }
    }
    println!("{:?}", head)
}