Format the date from vc bundle as \today

Question

I'm using the vc bundle to feed \date with the date from the latest git commit. Is there a way to format this date in the same format as the output from \today? I know of the different date formats in the vc bundle manual but none correspond to the format of today.

Here's an example to work with:

\immediate\write18{./vc}
\input{vc}
\documentclass{article}
\usepackage[utf8]{inputenc}

\title{[Title]}
\date{\VCDateISO}% I want to format this date...

\begin{document}

\maketitle

\today% ... like this date.

\end{document}

Answer 1

The VC manual states that \VCDateISO returns the date as YYYY-MM-DD. If this is the case you can use the following code to extract the three values and set TeX date registers accordantly. Then \today will return this date instead. This should of course happen inside a group.

%\immediate\write18{./vc}
%\input{vc}
\def\VCDateISO{2011-05-24}

\documentclass{article}

\makeatletter
\newcommand\VCDateToday{%
    \expandafter\@VCDateToday\VCDateISO\relax
}
\def\@VCDateToday#1-#2-#3\relax{%
    \begingroup
     \year=#1\relax
     \month=#2\relax
     \day=#3\relax
     \today
    \endgroup
}
\makeatother

\begin{document}

\VCDateToday

\end{document}

I can't test it myself because the VC bundle is not part of TeXLive or MikTeX and I don't want to install it manually just for that.

---

If you would use svn-multi instead you could simply use \svntoday. Contrary to what the VC documentation says the current version also support binary files.

Answer 2

With the isodate package, you can do this fairly simply:

\usepackage[american]{isodate}
\date{\printdate{\VCDateISO}}

Note isodate needs a language to be specified, so if you aren't using babel then you need to call a language option explicitly.

Awkwardly, american and english differ in how they print dates. Calling \usepackage[english]{isodate} changes how the date appears even just with \today.