Look up Jeni Tennison on Muenchian Grouping for an explanation of this XSLT 1.0 coding pattern.

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Michael Kay
http://www.saxonica.com/
Author, XSLT 2.0 and XPath 2.0 Programmer\'s Reference

I read Jeni's article on Muenchian Method and it makes sense, however, I am having trouble understanding why Martin uses concat and how the namespace-uri() with curly braces is being used.

Im sorry if this question has an obvious answer, I'm still very new at XSLT.

Thanks

I used concat on the namespace uri and the local name for the key value to make the XSLT 1.0 solution as close as possible to the XSLT 2.0 solution which groups on node-name(.). In an XML input document without any namespaces or with elements from only one namespace it would suffice to group (XSLT 2.0) or key (XSLT 1.0) only on the local name of elements but in general it is possible to encounter two elements of the same name but from a different namespace. In that case node-name(.) in XSLT 2.0 allows you to distinguish them but the function node-name is new in XSLT/XPath 2.0 so you can't use it with XSLT 1.0. Therefore I concatenated namespace uri and local name to make the posted solution capable of distinguishing two elements with the same local name but from different namespaces. The curly braces are used as that is an established notation (Clark notation I think) to represent a qualified name consisting of a namespace uri and a local name in one string.

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Martin Honnen
Microsoft MVP (XML, Data Platform Development) 2005/04 - 2013/03
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