This violates so many rules of the Unix philosophy that I don't even know where to begin...
Grep has issues with data blocks as well. "With regular expressions, you don't really have the ability to extract things that are nested arbitrarily deep," Weaver said.
If your data structures are so complex that diff/grep won't cut it, they should probably be massaged into XML, in which case you can use XSLT off the shelf. It's already customizable to whatever data format you're working with.
With [operational data in block-like data structures], a tool such as diff "can be too low-level," Weaver said. "Diff doesn't really pay attention to the structure of the language you are trying to tell differences between." He has seen cases where dif reports that 10 changes have been made to a file, when in fact only two changes have been made, and the remaining data has simply been shifted around.
No, 10 changes have been made. The fact that only two substantive changes have been made based on 10 edits is a subjective determination. That is, unless you want to detect that moving a block of code or data from one place to another in a file has no actual effect, in which case good luck because that's a domain-specific hard problem.