> 
> 
> (atom? 1)
#t
> (atom? 'a)
#t
> (atom? '())
#f
> (atom? '(1 2 3))
#f
> (atom? atom?)
#t
> (count-atoms dl)
0
> (count-atoms dl)
8
> (flatten dl)
(1 2 3 4 5 6 7 8)
> (deep-reverse dl)
(((() . 8) (((() () . 7)) (() () . 6) . 5) (() . 4) () . 3) (() () . 2) . 1)
> (deep-reverse dl)
(((() 8) (((() () 7)) (() () 6) 5) (() 4) () 3) (() () 2) 1)
> (deep-reverse dl)
(8 7 6 5 4 3 2 1)
> (deep-reverse dl)
[image] [image] mcar: contract violation
  expected: mpair?
  given: 7
> (deep-reverse dl)
((8) (((7)) () (((6)) (5)) ((4) ((3)))) (((2)) (1)))
> dl
((1 (2)) (((3) 4) (5 (6)) () (7)) 8)
> (deep-reverse dl)
(8 ((7) () ((6) 5) (4 (3))) ((2) 1))
> dl
((1 (2)) (((3) 4) (5 (6)) () (7)) 8)
> (deep-reverse dl)
((1 ((2 ()) ())) ((((3 ()) (4 ())) ((5 ((6 ()) ())) (() ((7 ()) ())))) (8 ())))
> (deep-reverse dl)
(((() 8) ((((() (() 7)) ()) ((() (() 6)) 5)) ((() 4) (() 3)))) ((() (() 2)) 1))
> (deep-reverse dl)
(8 ((7) () ((6) 5) (4 (3))) ((2) 1))
[image] read-syntax: expected a `)` to close `(`
> (deep-reverse dl)
[image] [image] snoc: undefined;
 cannot reference an identifier before its definition
> 
[image] read-syntax: unexpected `)`
> (deep-reverse dl)
(8 ((7) () ((6) 5) (4 (3))) ((2) 1))
> 
> (count-atoms dl)
8
[image] read-syntax: expected a `)` to close `(`
  possible cause: indentation suggests a missing `)` before line 27
> (flatten dl)
[image] [image] deep-foldr: arity mismatch;
 the expected number of arguments does not match the given number
  expected: 4
  given: 3
> (flatten dl)
(1 2 3 4 5 6 7 8)
> (foldr '() append dl)
[image] [image] foldr: undefined;
 cannot reference an identifier before its definition
> (foldr '() append dl)
[image] [image] application: not a procedure;
 expected a procedure that can be applied to arguments
  given: ()
> (deep-reverse dl)
[image] [image] deep-foldr: arity mismatch;
 the expected number of arguments does not match the given number
  expected: 4
  given: 3
> (deep-reverse dl)
(8 ((7) () ((6) 5) (4 (3))) ((2) 1))
> (count-atoms dl)
((1 (1)) (((1) 1) (1 (1)) () (1)) 1)
> (count-atoms dl)
8
> (flatten dl)
(1 2 3 4 5 6 7 8)
> (deep-reverse dl)
(8 ((7) () ((6) 5) (4 (3))) ((2) 1))
>