+\makeatletter
+
+%%%%% \IVS[<selector number>]{<character>}
+%%%%% or \IVS<selector number>{<character>}
+%%%%% (<selector number>: 0--239, or `?')
+\def\ltj@ivs@out#1#2{#2\char\numexpr "E0100+#1\relax} % IVS"
+\def\ltj@ivs@list?#1{\directlua{list_ivs('#1')}}
+\def\ltj@ivs@grab@num{\expandafter\expandafter\expandafter\ltj@ivs@out\ltj@grab@num}
+\def\ltj@ivs@nobracket{\@ifnextchar?{\ltj@ivs@list}{\ltj@ivs@grab@num}}
+\def\ltj@ivs@bracket[#1]{\ltj@ivs@nobracket#1}
+\def\IVS{\@ifnextchar[{\ltj@ivs@bracket}{\ltj@ivs@nobracket}}
+
+\let\MJI=\IVS
+