Why does sum (// *) return this response to this xml?

Question

This is xml

<a><b>2</b><c>3</c></a>

And this is an XPath request

sum(//*)

Which gives the following result:

Type: Num
Value : 28.0000

This is XPath 1.0.
Please explain the types of conversions (step by step).

Answer 1

Let me break it:

• //*will match the nodes a, bandc
• the function sum()will summarize the function call number()for each node
• the function will call node for each match number() string()
• the result number()for "a" is 23, for "b" it is 2, for "c" it is 3 -23+2+3=28