I'm keeping my homepage in a SVN repository; I'm using the $Date$ variable
to automatically track the last modification date (though it will also change
on minor modifications).
For the HTML "Date" meta tag, the W3C recommends using ISO8601 date format.
This is the (non-XSLT-2, so no regexp) hack I use for conversion:
<xsl:value-of select="concat(substring($string,8,4),'-',substring($string,13,2),'-',substring($string,16,2),'T',substring($string,19,8),substring($string,28,5))" />
Did I mention I hate XSLT? It's lacking so many standard functions, like
date-time processing, regular expressions, exceptions, ... - granted, a lot of
stuff was added for XSLT2, but it still sucks badly. Especially the syntax.
Here's how to format the date according to RFC 2616, as used in the
last-modified meta tag and HTTP/NNTP/SMTP headers:
<xsl:variable name="day" select="concat(substring($string,8,4),'-',substring($string,13,2),'-',substring($string,16,2))" />
<xsl:variable name="time" select="substring($string,19,8)" />
<xsl:variable name="timezone" select="substring($string,28,5)" />
<xsl:value-of select="date:day-abbreviation($day)" />
<xsl:text>, </xsl:text>
<xsl:value-of select="date:day-in-month($day)" />
<xsl:text> </xsl:text>
<xsl:value-of select="date:month-abbreviation($day)" />
<xsl:text> </xsl:text>
<xsl:value-of select="date:year($day)" />
<xsl:text> </xsl:text>
<xsl:value-of select="date:time($time)" />
<xsl:text> </xsl:text>
<xsl:value-of select="$timezone" />
Note that this does not include any error handling and is not very robust.
You also need an XSLT processor with some of the
">">">http://exslt.org/dates-and-times
extensions such as
xsltproc.
(Which unfortunately doesn't do XSLT2 yet and doesn't have a regexp extension).
[Update: Joel Wreed pointed me to his
libxslt plugins, a regexp
and a exsl.org/dates-and-times plugin. These would help a lot, though IIRC the
date-parse exsl.org spec doesn't support the date format I'd need. (So I
can't just say date-format(date-parse(...),...)). Also he said that they
basically are unmaintained right now. It would be nice if they could be merged
into libxslt, though...]
