Case-insensitive XPath queries

[Robert Sander]

Hi,

I have to do some case-insensitive queries on a XML document using XPath.
Because XML 1.0 and XPath 1.0 are case-sensitive this is a little bit tricky.

Sample document:

<books>
<book>…</book>
<Book>…</Book>
<BOOK>…</BOOK>
</books>

I want to select all book elements. A query like

“/books/book�

returns just one (the lower-case) element.

One possibility is to work with the transform XPath function but that seems
to be not a very performant solution.

Another way is to write a custom XPath function that implements a to-lower
functionality. Given such a function, I could write a query like

“/books/*[abc:to-lower(local-name(.))='book']�

Before I start the editor: Are there better/alternative solutions?

Thanks,

Robert

[Oleg Tkachenko [MVP]]

Robert Sander wrote:

One possibility is to work with the transform XPath function but that seems
to be not a very performant solution.

Another way is to write a custom XPath function that implements a to-lower
functionality. Given such a function, I could write a query like

“/books/*[abc:to-lower(local-name(.))='book']�

Before I start the editor: Are there better/alternative solutions?

Usual trick is to leverage translate() function to change the case:
“/books/*[translate(local-name(), 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
'abcdefghijklmnopqrstuvwxyz')='book']�

Obviously it's english only solution.
EXSLT.NET provides str2:lowercase() function, which is i18n-friendly -
http://xmland.net/exslt/doc/GDNStrings-lowercase.xml

--
Oleg Tkachenko [XML MVP]
http://blog.tkachenko.com