What is XML's sweet spot?

["Costello, Roger L." <costello@mitre.org>]

Hi Folks,

The recent discussion titled "Protocol Buffers - Why not use XML" was very interesting. Of particular interest to me was the discussion's sub-theme: 

	What is XML's sweet spot?

Here are excerpts from some of the responses:

Liam Quin, the XML Activity Lead for the W3C wrote [1]:

	[XML's] sweet spot was and remains encoding, archiving, 
	interchange & processing of complex documents

	the Enterprise XML people (Web Services) and the "XML is 
	to replace HTML" people managed to scare away a lot of 
	potential XML users

Arjun Ray wrote [2]:

	the authors [of a paper criticizing XML] do go wrong in 
	characterizing XML as a "mechanism for serializing structured
	data", which is precisely where all the bad karma originates.

	if the question is "a flexible, efficient, automated mechanism for
	serializing structured data", then just about all of the time XML is
	_not_ the answer.

	But how about marking up documents - where free flowing text and
	annotations are the rule [XML is well-suited to handle this]

So what does all that mean? Here's what I think Liam and Arjun are saying:

1. Use XML when you have complex documents, such as the kind of semi-structured documents that Word creates. So an XML encoding of a Word document is a good use of XML.

2. Use XML when you have free-flowing text and you want to periodically insert markup on certain portions (e.g., put a <name>...</name> tag around each name in a body of text). In XML terminology, these are "mixed content" documents.

3. XML is well-suited to data that needs to be archived and used 5, 10, 50 years from now.

4. XML is not well-suited as a data exchange format for web services. There are better formats for this, such as JSON, Protobufs, AVRO, Thrift.

5. XML + XSLT is not a good substitute for HTML.

That's how I interpret their comments. Is that how you interpret their comments? Do you agree with them?

/Roger

[1] http://lists.xml.org/archives/xml-dev/201602/msg00005.html 

[2] http://lists.xml.org/archives/xml-dev/201602/msg00011.html