> I'd be delighted if someday there's an OS which requires things sent into another program to adhere to an open and well defined data formatting standard, and

> I'd be delighted if someday there's an OS which requires things sent into another program to adhere to an open and well defined data formatting standard, and just one at that Emacs? Jokes aside, I really do think S-exprs would be a good candidate for what you’re talking about as they can represent the same structures as JSON et al with less ceremony. Since S-exprs separate atoms with whitespace, and most UNIXy programs parse structured text using whitespace, you could implicitly wrap those programs’ input/output with parens to make them work on S-exprs.