RIE is rust interactive editor.
REPL-like expirience based on interactive source code editing.
```
:2 * 2 = 4
:x * 2 = 4
:f(4) = 16
% 0 fn main() { 1 let x = 2; 2 let f = |x : i32| x * x; 3 } %d 2 0 fn main() { 1 let x = 2; 2 } ```
% 0 fn main() { 1 let x = 2; 2 let f = |x : i32| x * x; 3 } %d 2 0 fn main() { 1 let x = 2; 2 }