When the article's author describes both code and data using JSON, it sounds a little strange to me. While JSON is capable to describing nested data structures, JSON's syntax is much more verbose than s-expressions. I feel that since s-expressions have been around for about 60 years that the author should be familiar with them and address why a JSON encoding is superior to s-expressions for this use case.

1 - https://en.wikipedia.org/wiki/S-expression

2 - http://wiki.c2.com/?DataAndCodeAreTheSameThing

    "The interchangeability of code and data gives Lisp its instantly recognizable syntax. All program code is written as s-expressions, or parenthesized lists. A function call or syntactic form is written as a list with the function or operator's name first, and the arguments following; for instance, a function f that takes three arguments would be called as (f arg1 arg2 arg3)."