Is XML a "data structure"?

Hi Folks,

A compiler book [1] that I am reading has a chapter on code optimization for the target machine. In the chapter it talks about how to break up the code into "basic blocks". This sentence struck a chord for me:

"A suitable data structure for basic blocks is a linked list, such as this ..." (the book then shows a C struct)

A suitable data structure ... 

Hmm, that's an interesting expression. Suppose that instead of basic blocks, I have book data - title, author, publisher, etc. What is a "suitable data structure" for that? Well, obviously XML!

Is XML a data structure?

/Roger

[1] "Introduction to Compiling Techniques" by J.P. Bennett, page 166.