On Mon, Jun 6, 2016 at 11:06 AM, Dale R. Worley <[email protected]> wrote:
> A difficulty I have with the current wording is that it doesn't point > out the crucial fact about leafref that the XPath expression can only > select elements that are instantiations of one particular data node. I > don't know XPath, but it seems that that is not a general property of > XPath expressions, you seem to be able to write XPath expressions that > select heterogenous groups of elements. So it's worth pointing out that > the allowed XPath expressions can't do that, and that is because of the > restriction that the expression must match path-arg. > > Perhaps my problem is that XPath is almost always used in this style, > and so the limitations in leafref aren't anything unusual. > > I can say that the implementation details are much easier than the convoluted text might imply. 1) the value MUST be valid for the final "type" statement. The server validates that the value is valid for the type of the pointed-at leaf. (Or final pointed-at leaf if it is also a leafref). 2) If require-instance is true then the value MUST also be in use by the first pointed-at leaf. i.e., the value is valid for the data type and there exists an instance of the pointed-at leaf with the same canonical value > Dale > Andy > > _______________________________________________ > netmod mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/netmod >
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