Interactive error messages for the Julia REPL. Just start using your REPL normally. Once you hit an error you'll be presented with an interactive tree representing your stacktrace which you can explore. To turn interactive errors off and return to using normal stack traces call toggle(). Call toggle() again to turn it back on. Press up and down arrows to move through the stacktrace. Press space to fold or unfold the currently selected line. A + will appear on folded lines. Press enter once...