XPath query result order

Question

For another question I have created some XML related code that works on my development machine but not on viper codepad where I tested it before adding it to my answer.

Answer 1

Technically XPath 1.0 returns node-sets rather than node sequences. In the XPath 1.0 specification there is no statement about the order of these node-sets - indeed, being sets, they have no intrinsic order.

However, XSLT 1.0 always processes the node-sets returned by XPath 1.0 in document order, and because of that precedent, there is a widespread expectation that XPath results will be in document order when XPath is invoked from languages other than XSLT. However, there is nothing in the spec to guarantee this. In XPath 2.0 the user expectation becomes part of the spec, and the results of a path expression MUST be in document order.