Re: [xdi] Re: Proposal about null vs. undefined values

How an XDI server should respond to an attempt to retrieve the value from an address where none has been assigned is a different matter to be specified by the XDI Messaging protocol(s). The result could be considered an error code or value, but should not be conflated with values of the JSON space, which should be reserved for client data with the client's choice of semantics.

On Aug 18, 2013, at 10:21 AM, Joseph Boyle <planetwork@josephboyle.net> wrote:

On Aug 18, 2013, at 8:53 AM, Markus Sabadello <markus.sabadello@xdi.org> wrote:

I am against introducing such a semantic distinction for the reasons I already mentioned.
When storing data, either it is there or it is not there.
I don't know of any data model that distinguishes between the three states null, not null, and undefined.

In general I find the approach of comparing XDI to programming languages (Java, _javascript_, Perl, ...) quite useless.

I also find the following sentence from the XDI TC minutes inapplicable since it only talks about one specific JSON implementation rather than the general concepts:
"Java’s null is not equivalent to JSON null but to JSON undefined"
http://json-lib.sourceforge.net/apidocs/jdk15/net/sf/json/JSONNull.html

The point of that note was just to further warn against equating JSON null with any particular semantics, even with no-value-assigned in XDI, because "null" can have completely different meanings in various contexts. It is arguing for independence from ciients' various programming languages, not for dependence on them.

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