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> as everything is a node, one can match a node like this : > node() I assume we're talking about XPath path expressions here, not XSLT match patterns: so it might be better to use the verb "select" rather than "match". Yes, node() is short for child::node(), it selects any node on the child axis. > which works well in the axis that are walking through the tree > what about other axis ? > @node() > namespace::node() > which would give the same as (respectively) : > @* > namespace::* Correct. > and above all what about : > @comment() > @text() > @p-i(target) > namespace::comment() > namespace::text() > namespace::p-i(target) > which are all empty if they are legal > > but are they legal ? Yes, they are legal in XPath 1.0. They all select an empty set of nodes. In XPath 2.0, with static typing, they have a static type of empty-sequence(), which is a type error that can be reported at compile time if the processor chooses to do static type checking. > > here are the last ones : > /@* > /namespace::* > Again these are legal, and select nothing. The same applies to, for example, @*/@* > > > Will you be hurted if someone (like me) was writting > something like this : > $foo/@bar/@oof > If your data conforms to the XPath data model, then this will select nothing. If you want to design a language similar to XPath that works on a different data model, for example one in which attributes can have attributes, then you are free to do so (but please don't call it XPath). Michael Kay http://www.saxonica.com/
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