# Lightning symbol with LuaTex

I'm trying to use the lightning symbol ↯ in my document. I use luatex. If I understand correctly I do not need the command

\unicode{x21af}


but I can write ↯ directly in my document. My problem is that the symbol does not appear in the generated pdf. Thus, I guess, the symbol is not contained in the font used in the pdf.

If I have no error, how to I influence the chosen font? I should find a font with the symbol.

\documentclass{article}
\usepackage{graphicx}
\begin{document}
(↯)
\end{document}

• May be some of the necessary (or all of the) font package(s) pretaining to that particular font class is missing? – Raaja Nov 5 '18 at 10:44
• Which package defines the macro called \unicode? – Mico Nov 5 '18 at 11:42
• @Raaja, very good! I installed texlive-stmaryrd, added \usepackage{stmaryrd} and now \lightning gives me the needed symbol – PeptideChain Nov 5 '18 at 12:03
• See fileformat.info/info/unicode/char/21af/fontsupport.htm to find fonts that support the character. – Thérèse Nov 5 '18 at 12:29
• @PeptideChain, a side note : for such questions, you can try detexify, very useful tool ! – BambOo Nov 5 '18 at 13:04

As you guess, it's just a matter of choosing a font containing the glyph. You do this using fontspec. (Update to use \newunicodechar courtesy of @egreg.)

\documentclass{article}
\usepackage{fontspec}
\usepackage{newunicodechar}
\newfontfamily\symbola{Symbola}
\newcommand{\downzigzagarrow}{\begingroup\symbola ↯\endgroup}
\newunicodechar{↯}{\downzigzagarrow}
\begin{document}
Filler text ↯ Filler text
\end{document}


• You can accompany this with \usepackage{newunicodechar} and \newunicodechar{↯}{\downzigzagarrow} after defining \downzigzagarrow so it's possible to use ↯ directly in the document. – egreg Nov 5 '18 at 13:04
• @egreg, no way. I never knew that. – David Purton Nov 5 '18 at 13:07
• I know the package, guess why. ;-) – egreg Nov 5 '18 at 13:09