[xquery-talk] File Systems & XQuery
frans.englich at telia.com
Wed Feb 7 16:42:33 PST 2007
On Wednesday 07 February 2007 16:13, Michael Kay wrote:
> Kristoffer Rose of IBM Research has demonstrated this kind of idea, but I
> can't find a reference at the moment.'
And when you bring up the topic of prior art, I vaguely recall a post on
xml-dev about file system utilities and XPath:
Notably, Eric van der Vlist mentions how to deal with invalid XMLName
characters in file names, if one chooses the
"/home/fenglich/projects/"-approach. So, I conclude that only supplying that
approach is a no-go.
Another problem is how to query a certain directory when the user has a URI,
as opposed to a path known when writing the query. One could probably write a
recursive function that splits the URI, but that is error prone and hackish.
Especially considering that this is probably a rather common scenario.
Here's a new angle:
I wonder if it's justifiable to get excited about "$fs/home/fenglich". It is
the URI syntax duplicated with an XPath path -- talk about over engineering.
Phrased differently: if one knows the path at query-writing time, one can
just as well write it as a URI.
The problem though, is that in that case one can't use fn:collection()(unless
one decide to use the fragment, in some horrible way), but most likely must
resort to a function. Not as simple, but it also opens up the door for
inspecting file systems other than the local, such as FTP and Samba volumes.
Skipping fn:collection() in favour of extension functions(or depending on
where such a spec is developed..) makes it more acceptable to add other
functions, if one would need such. I was considering formatting of file
sizes, but perhaps that is an idea that definitely should be killed as
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