Tcl/Tk Binding % Substitutions

How should we translate something like the following?

Tcl> bind Frame <Enter> {%W config -bg red}

such that the widget id (and other % substitutions) can be accessed
in R callback?

one <- tkframe(width=30, height=30)
tkbind("Frame",
            "<Enter>",
            function(TBD} {
                ## Do whatever...
            })