# Siunitx + Junicode font: Overfull hboxes

The following MWE, using Junicode, creates 4 overfull hboxes. But any other font I tried (e.g. Linux Libertine O) creates no warnings. Any ideas?

\documentclass{article}

\usepackage{fontspec}
\setmainfont[Numbers=OldStyle]{Junicode}% Generates 4 overfull hboxes
%\setmainfont[Numbers=OldStyle]{Linux Libertine O}% No overfull hbox

\usepackage{siunitx}

\begin{document}

\begin{tabular}{l*{4}{S[table-format=1.3]}}
&\multicolumn{1}{c}{Column 1}&\multicolumn{1}{c}{Column 2}\\
&  0.234                        &0.095             \\
\end{tabular}

\end{document}

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The old style digits in Junicode don't have the same width. If I use 1.111 I don't get overfull boxes, so I guess the digit used for setting the width is 1. –  egreg Jun 8 '12 at 12:54
As @egreg says, the key here is that siunitx 'expects' a single width for numerals in tables. Turning off the number parser (parse-numbers = false) is perhaps the best way to deal with variable-width characters in tables. –  Joseph Wright Jun 8 '12 at 17:13
@JosephWright Using a different digit for doing the measurement wouldn't align the digits anyway. One should use fixed width digits for tables with numeric data. –  egreg Jun 8 '12 at 17:21
@egreg My point is that using the parse-numbers = false approach does the decimal alignment in a different way, so you should not get overful boxes. It will not look good, but ... –  Joseph Wright Jun 8 '12 at 17:42
@JosephWright Uh, parse-numbers = false is, I think, not really an option :). But is siunitx concept of expecting a single width (and setting the width to the width of "1") not a slight conceptional problem? If I am not mistaken, there are quite a few fonts that do not have tabular/monospaced figures, i.e. this error might occur frequently. Would it not be better to set the width to, let's say, "6" or "8"? –  Jörg Jun 8 '12 at 17:55
Most fonts have fixed-width numerals, at least as standard. Some fonts do provide variable width numerals, but usually as an alternative to the fixed size things. For those that do, using fixed ('tabular') numbers in tables is still recommended as otherwise you cannot get alignment. As such, an option for this is not really that widely useful in siunitx, although you are welcome to open a feature request.