* * * * *

Long dull posting about site construction, reconstruction, reformatting, XML,
                      XSL, XPath and other alphabet soup

One of the reasons (okay, possibly the reason) I don't update my personal
site [1] all that often is that it's a pain to update. Just to add a new
portrait [2] involves editing two pages (sometimes three, depending upon the
format of the image), and creating a new page. Between the creating, editing
and testing it takes something like fifteen to twenty minutes before I'm
done, and that's fourteen to nineteen minutes too long.

Why so much editing to add a picture?

Mostly for the navigation aspects of the site. I remember, oh, this must have
been in '96, '97, having this huge discussion (okay, argument really) with my
friend Eve about site structure and the (at the time) lack of navigation
elements on my site. I was dreading having to edit some 100 pages but her
argument (“Sean, what if I show one of your pages to some hot babe and she
wants to see your picture? There's no easy link to a picture of you!”)
finally convinced me to dive in and edit over 100 pages to add navigation
links. While I was at it, I also added <META> and <LINK> tags as well.

Painful process, that.

And it's maintaining the relationship between pages that consumes so much
time when adding a new page (not to mention that I technically, should add
new pages to the sitemap [3] but haven't, and that only one in six links on
my gratuitous links to people I know, or just like their webpages [4] still
work, leaving five out of six broken but that's another issue right now) that
is a complete drag on updating the site. Years ago I thought of writing
software to maintain the pages in one form, then feed them through a template
engine to generate all the navigation and meta-information but never really
got around to it, although I still have the notes floating around somewhere
on my harddrive.

So now here it is—October of 2002 and my site hasn't changed its look since
at least 1998, possibly longer (I want to say 1996, but that might be too
early). I'd like to convert over to using CSS (Cascading Style Sheets), and
improve the navigation links (mostly by taking advantage of the <LINK> tag)
but that means I have to edit 145 pages.

If I'm going to be making such drastic changes, I might as well rethink how
the site will be generated while I'm at it. And what I had originally wanted
in a templating engine seems to exist in XSL (eXtensible Stylesheet Language)
[5]. Nice if my pages are in XML (eXtensible Markup Language) but right now,
they aren't. So as long as I'm editing them anyway I might as well convert.

And converting I have. And I've found some rather odd aspects about XSL
(eXtensible Stylesheet Language) and XPath (XML Path Language) [6] (which is
used to reference portions of an XML document). I'm building the navigation
links within the template, so to generate a link to the next page I have:

> <xsl:if test="position()!=last()">
> <link
>  rel="next"
>  title="{following-sibling::column/child::title}"
>  href="{following-sibling::column/attribute::filename}.htm"
> />
> </xsl:if>
>

Basically, following-sibling::column/child::title gets the following column
from the input file and extracts the title, and following-
sibling::column/attribute::filename gets the filename of the following
column. Pretty straightforward. To get a link to the previous column, there's
a corresponding preceding-sibling:

> <xsl:if test="position()!=1">
> <link
>  rel="previous"
>  title="{preceding-sibling::column/child::title}"
>  href="{preceding-sibling::column/attribute::filename}.htm"
> />
> </xsl:if>
>

Easy, strightforward and hopelessly wrong.

That kept generating a link to the first [7] column. Now, since the phrase
preceding-sibling::column returns all the columns preceeding the current one,
the engine looks like it is returning the title to the first column. So I
thought that selecting the last column of the preceding columns would do the
trick:

> <xsl:if test="position()!=1">
> <link rel="previous"
>  title="{preceding-sibling::column[position()=last()]/child::title}"
>  href="{preceding-sibling::column[position()=last()]/attribute::filename}.htm"
> />
> </xsl:if>
>

Nope. Still getting the last column. Hmmm … check up on preceding-sibling:

> All nodes that precede the context node and are contained in the same
> parent element node in reverse document order.
>

Okay.

So let's see what happens when I return the first column of the preceding
columns:

> <xsl:if test="position()!=1">
> <link rel="previous"
>  title="{preceding-sibling::column[position()=1]/child::title}"
>  href="{preceding-sibling::column[position()=1]/attribute::filename}.htm"
> />
> </xsl:if>
>

Okay, that works!

Very intuitive, that.

So, outside some wierdness like that, the conversion process is slowly making
progress.

[1] http://www.conman.org/people/spc/
[2] http://www.conman.org/people/spc/about/
[3] http://www.conman.org/people/spc/refs/
[4] http://www.conman.org/people/spc/people/
[5] http://www.w3.org/Style/XSL/
[6] http://www.w3.org/TR/xpath
[7] http://www.conman.org/people/spc/writings/murphy/ml101.html

Email author at [email protected]

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