\newcount\res
\def\test#1{%
  \setbox0\hbox{#1\global\res=\lastnodechar\global\xdef\rf{\the\lastnodefont}}%
  \leavevmode\hbox to 5em{\hss \the\res}, \hbox to 10em{\tentt\meaning\rf\hss}%
  \copy0\par}

\global\res=\lastnodechar\xdef\rf{\the\lastnodefont}\the\res. {\tentt \meaning\rf}

\ybaselineshift-10pt
\setbox0\vbox{\vskip10pt\global\res=\lastnodechar\global\xdef\rf{\the\lastnodefont}}%
\leavevmode\hbox to 5em{\hss \the\res}, \hbox to 10em{\tentt\meaning\rf\hss}%

\test{}
\test{a}
\test{ffi}
\test{漢）}
\test{漢字}
\hbox{\tate \test{漢字}}
\test{あ\kern-1pt}
\test{あ\hskip10pt}
\test{あ\/}


\bye
