Macro doe::btreemap

macro_rules! btreemap {
    () => { ... };
    ($(||)+) => { ... };
    ($($k: expr => $v: expr),+ $(,)*) => { ... };
}

macro for BTreeMap

 use doe::*;
 use std::collections::BTreeMap;
 let mut map:BTreeMap<i32,i32> = btreemap!();
 map.insert(0, 1);
 let map1 = btreemap!(2=>5,3=>4);