When people say 'code is data' they obviously don't mean that source code is stored in a text file which consists of bytes...

(def add (x y) (+ x a))

(def sub (x y) (- x y))

(add 1 2) # 3

(sub 1 2) # -1

(first '(add 1 2)) # 'add

(rest '(add 1 2)) # (list 1 2)

(apply 'sub (rest '(add 1 2))) # -1

(reverse '(add 1 2) # '(2 1 add)

Excuse my pseudo lisp quote syntax, it's been a while.