Welcome to DrScheme, version 205.
Language: Standard (R5RS).
> (atomcount '(1 (2 3)))
3
> (length '(1 (2 3)))
2

> equal?
#<primitive:equal?>
> (eq? 3 3)
#t
> (eq? 'a 'a)
#t
> (= 3 3)
#t
> (= 'a 'a)
. =: expects type <number> as 2nd argument, given: a; other arguments were: a
> (define a 3)
> (eq? a 3)
#t
> (eq? ((lambda (x) (+ x 1)) 2)  3)
#t