XML Schema and CFG

[solid]

Is XML Schema a CFG or is it a Context Sensitive Grammar? I believe
that a general XML is not CFG, but need a proof.
Are other XML grammar descriptions such as Relax NG Context Free? (If
so, is it proven anywhere).

 

[Joseph Kesselman]

STFW... Websearch says the W3C's XML Schema language is not
context-free, and includes some discussion of why. See, for example,

http://www.w3.org/2000/04/26-csrules.html

 

[Joseph Kesselman]

Is XML Schema a CFG or is it a Context Sensitive Grammar?

Websearch says "rough equivalent of a context-free grammar", but also
shows examples of using explicit typing to impose context-sensitivity.
So the answer appears to be that a _particular_ schema could be either.