%%
%% The LaTeX Companion, 3ed
%%
%% Example 9-6-14 on page I-719 in "Vertical positioning features".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{81.0pt}

  %!TEX program = lualatex

  \setlength\parindent{0pt}

%StartShownPreambleCommands
\usepackage{fontspec}   \setmainfont{Noto Serif}
\setsansfont{Noto Sans} \setmonofont{NotoSansMono-Condensed.ttf}
\newcommand\txtfrac[2]{{\addfontfeature{VerticalPosition=Numerator}#1}%
                    /{\addfontfeature{VerticalPosition=Denominator}#2}}
%StopShownPreambleCommands

\begin{document}
          \txtfrac{1}{2} \txtfrac{47}{11} \txtfrac{1}{1000} \par
\sffamily \txtfrac{1}{2} \txtfrac{47}{11} \txtfrac{1}{1000} \par
\ttfamily \txtfrac{1}{2} \txtfrac{47}{11} \txtfrac{1}{1000}
\end{document}