Macro wrap 

macro_rules! wrap {
    () => { ... };
    ($from:ty) => { ... };
    (=> $to:ty) => { ... };
    ($from:ty => $to:ty) => { ... };
}

Provides a closure, which captures a new Frame in the invocation place and wraps the given error into a Traced wrapper containing this Frame.

If the error represents a Traced already, then just growths its Trace with the captured Frame.

Example

use tracerr::Traced;

let res: Result<(), u32> = Err(89);
let err: Traced<u32> =
    res.map_err(tracerr::wrap!()).map_err(tracerr::wrap!()).unwrap_err();