Both, Python and Common Lisp have libraries for writing and reading JSON format. JSON can be used as an alternative to XML, when not only machines will read the data. XML can be hard to read when you have more tags than data. JSON does not have the overhead of start and end tags.

In Python, you can import module json from the Python standard library.

>>> import json
>>> a = [1, 2, 3]
>>> json.dumps(a)
‘[1, 2, 3]’
>>> json.loads(‘[1, 2, 3]’)
[1, 2, 3]

In Common Lisp, you can use the CL-JSON library.

CL-USER> (ql:quickload “CL-JSON”)
CL-USER> (cl-json:encode-json ‘(1 2 3))
[1,2,3]
NIL
CL-USER> (with-input-from-string (s “[1, 2, 3]”) (cl-json:decode-json s))
(1 2 3)

These are just very simple examples, but you see that usage is straightforward. If you don’t like the syntax of JSON, you might want to have a look at YAML. JSON is a subset of YAML version 1.2.