next and nextto, built-in Tcl commands, in TclOO allow a method to call an upstream method that it has overridden.
In TclOO/Tcl 8.6:
next in TclOO is inspired by XOTcl's eponymous command, and the semantics are slightly different. TclOO's next effectively does an uplevel inside itself.
nextto selects the method according to class.