I know I can make *hello*
produce hello in bold typeface. But how would I, in addition, make **hello**
produce hello in italics?
\documentclass{article}
\begingroup\lccode`\~=`* \lowercase{\endgroup\def~#1~}{{\bfseries #1}}
\catcode`*=13
\begin{document}
*this is bold typeface* % works
**this should be italic typeface** % how to do this?
\end{document}