One can use [`.find_equiv`](http://static.rust-lang.org/doc/master/std/hashmap/struct.HashMap.html#method.find_equiv) to avoid the `~str`s, e.g. `m.find_equiv(& &"word")`. Unfortunately, the two `&`s are required to get a `& &str`, and the space is required because otherwise it gets tokenised as `&&` `"word"` (i.e. logical and), which it doesn't handle (this is a bug).