Typesetting Roman numerals within LaTeX text

Question

I want to typeset real Roman numerals (both uppercase and lowercase) in LaTeX text. I've checked out a previous thread but found no satisfactory solution. (In fact, several solutions mentioned in that thread doesn't work for me. I don't know why.)

I personally use the straightforward approach of

    \newcounter{counter}       
    \newcommand{\upperRomannumeral}[1]{\setcounter{counter}{#1}\Roman{counter}}
    \newcommand{\lowerromannumeral}[1]{\setcounter{counter}{#1}\roman{counter}}

but it is still not satisfactory. Is there any better way to perform the task?

Answer 1

Usually Roman numerals are used with counters for enumerated lists or as numbers for sectional units and the \roman and \Roman facilities do just this.

If all you want is to print some number in Roman numerals, here are two easy macros:

\newcommand{\upperRomannumeral}[1]{\uppercase\expandafter{\romannumeral#1}}
\newcommand{\lowerromannumeral}[1]{\romannumeral#1\relax}

Thus you can write

The king Louis~\upperRomannumeral{14} was called ``le roi soleil''

but typing Louis~XIV would be clearer and shorter.

Answer 2

If I understand you right, it seems like you are after in-line lists that are numbered in Roman numerals. I think the enumitem package is up to the job for this kind of thing.

Code

\documentclass[preview,border=5]{standalone}

\usepackage{enumitem}

\newlist{inlineroman}{enumerate*}{1}
\setlist[inlineroman]{itemjoin*={{, and }},afterlabel=~,label=\roman*.}

\newcommand{\inlinerom}[1]{
\begin{inlineroman}
#1
\end{inlineroman}
}

\newlist{Inlineroman}{enumerate*}{1}
\setlist[Inlineroman]{itemjoin*={{, and }},afterlabel=~,label=\Roman*.}

\newcommand{\InlineRom}[1]{
\begin{Inlineroman}
#1
\end{Inlineroman}
}

\begin{document}
I would like to cite some properties. Here are the properties listed in-line using small Roman numerals: \inlinerom{\item first, \item second \item third.}

Here are other properties listed as capital Roman numerals: \InlineRom{\item First property \item Second property \item Third property.}
\end{document}

Output

Answer 3

You might try using the biblatex package. It has a \RN command that does uppercase roman numerals. That way you don't have to create your own command. biblatex is usually loaded to do bibliographies, but it does the roman numerals as well.

Answer 4

If you use the xparse package, then you can very nicely define a single command which will set the roman numerals in upper or lower case depending on whether or not there is a star to the command name.

Here is a MWE which uses a counter

\documentclass{article}
\newcounter{myromanumeral}
\usepackage{xparse}
\NewDocumentCommand{\myrm}{s m}
    {\setcounter{myromanumeral}{#2}%
     \IfBooleanTF #1{\Roman}{\roman}{myromanumeral}}
\begin{document}
Hello, does this work \myrm{19}?  Or this \myrm*{19}?
\end{document}

If you really don't want to use a counter you can do something like the following:

\makeatletter
\NewDocumentCommand{\myrmo}{s m}
    {\expandafter\def\csname c@my@private@counter\endcsname{#2}%
     \IfBooleanTF #1{\Roman}{\roman}{my@private@counter}}
\makeatother

Please notice how in my code I use % at the end of the lines. This prevents extra space from creeping in where I don't want it.

If you want to stick with your own commands, then rewrite them as

\newcounter{counter}

\newcommand{\upperRomannumeral}[1]{%
    \setcounter{counter}{#1}%
    \Roman{counter}%
}

\newcommand{\lowerromannumeral}[1]{%
    \setcounter{counter}{#1}%
    \roman{counter}%
}

Answer 5

What worked for me was

\newcommand{\Rom}[1]{\uppercase\expandafter{\romannumeral#1\relax}}

This allowed me to use it with chapter references, e.g., \Rom{\ref{chap:conclusion}}.