An unknown exception was thrown when the command was being run, whether from the command itself or within Ammonite's own machinery.
The user wanted to exit the REPL
Failing results never call their callbacks, and just remain unchanged
A known failure occured, maybe caused by an exception (e.g.
the message we want to display on screen due to this failure
Successes map and flatmap just like a simple Box[T]
Nothing was entered
Maps a Res-returning function across a collection
M[T], failing fast and
bailing out if any individual element fails.