Re: [Saxdotnet-devel] String.Empty vs. null

[Jeff R. <li...@je...>]

> One of the things Elliotte mentioned was passing the URI to
> other libraries, instead of checking it. That is what D.Megginson probably
> meant with convenience. So, which libs in .NET would one use?
> And what do they accept? It would be funny if after all the
> discussion they accepted null for an URI.

Elliotte also mentioned that he didn't like to include if (uri == null) 
everywhere-- and that knowing the uri would never be null saved him from 
the clutter.

> I am hesitant to dictate my opinion here. In the end, anything is workable.
> Unfortunately not too much feedback.

So you are a benevolent dictator... I like that...

> If we go with String.Empty for URIs and prefixes, then I would suggest
> they should be the only such case, as then we would be pretty much in 
> agreement
> with the original Java API, and the work effort to change all other such
> API cases and their implementations could be quite inconvenient.

100% agree...

>> In any event-- we need to decide, we need to document the decision 
>> very clearly and we need to make sure our SAX conformance application 
>> checks for all of the appropriate cases. Which may involve adding a 
>> secondary test suite.
> 
> Yes, definitely.

As a side note-- the Java SAX Conformance suite relies on the fact that 
the URI will not be null (as a side affect). Anything that does not do 
so is not "SAX Conformant" according to Elliotte's suite. Now, I think 
that is wrong because it is not legislated-- but every parser he tested 
is conformant on that point... meaning they all pass string.empty and 
not null.

===============
The XmlReader.NamespaceURI has this:

   Property Value
   The namespace URI of the current node; otherwise an empty string.

   Remarks
   This property is relevant to Element and Attribute nodes only.

In XmlDocument.CreateElement:

   namespaceURI
   The namespace URI of the new element (if any). String.Empty and a
   null reference (Nothing in Visual Basic) are equivalent.

In XmlElement.NamespaceURI:

   The namespace URI of this node. If there is no namespace URI, this
   property returns String.Empty.

And finally, XmlNamespaceManager.AddNamespace Method throws an 
ArgumentNullException in the case:

   The value for prefix or uri is a null reference (Nothing in Visual
   Basic).
===========

This all seems pretty compelling... :)

Jeff