comment

Ignores all body forms (i.e. "commenting out"). Returns nil.

This is often used near the bottom of a file to hold expressions that test different functions during development. Specific expressions within the comment can then be selected and evaluated from some editors.

You can also use ; to "comment out" code until the end of a line.

(comment 123)
;;=> nil

(comment
  (foo 1 2 3)
  (bar "hello"))
;;=> nil

Inner forms must still be syntactically correct:

(comment [1 2 3]])
;; Error: Unmatched delimiter ]

(comment a : b)
;; Error: Invalid token :