Expressions in

About Expressions

Everything in Common Lisp is an expression. An expression is either a single thing (called an atom) or a list of things (delimited with parenthesis: ()).

Quoting

All S-Expressions, like symbols, can be quoted:

;; This line is evaluated as code
(gimme-foo)  ; => FOO

;; This line is treated as data
'(gimme-foo) ; => (GIMME-FOO)

This quoting prevents the evaluation of an S-expression, instead treating it like data. Here is an excellent Stack Overflow Answer discussing quoting in a bit more detail.