1. Examples of using current() & deref() in XPath
oimt2019.KL _XPath-current-deref
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2. XPath in YANG 1.1 – RFC 7950 XPath – XML Path Language
YANG relies on XPath 1.0 as a notation for specifying inter-node references and dependencies
In RFC 7950 – YANG 1.1
6.4 XPath Evaluations: XPath Context, examples
10 XPath Functions:
10.1 Node Sets
current()
node-set current()
The current() function takes no input parameters and returns a node set with the initial context node as its only member.

3. XPath in YANG 1.1 – RFC 7950 In RFC 7950 – YANG 1.1
6.4 XPath Evaluations: XPath Context, examples
10 XPath Functions:
10.1 Node Sets
current()
10.3 YANG Types leafref & instance- identifier
deref()
node-set deref(node-set nodes)
The deref() function follows the reference defined by the first node in document order in the argument "nodes" and returns the nodes it refers to

4. XPath in YANG 1.1 – RFC 7950 Use of deref() and current() in XPath
deref() is needed when you need to follow a leafref to the leaf it is pointing to
current() is needed to get the current element
Beniot Example (via Scott)
There are authors and books. A book has an author. You want to make sure the author has an account-id.
So the current() returns author. To get to the account-id, you need to follow the leafref to /authors/author/name, then backup a level in the tree and then down to account-id. Just like navigating paths in unix.

5. THANKS! 