> (id id)
#<procedure:id>
> (twice square)
#<procedure:...me/highorder.scm:40:2>
> ((twice square) 2)
16
> (twice (twice square))
#<procedure:...me/highorder.scm:40:2>
> ((twice (twice square)) 2)
65536
> ((twice twice) square)
#<procedure:...me/highorder.scm:40:2>
> (((twice twice) square) 2)
65536
> n+
#<procedure:n+>
> (n+ 1)
#<procedure:...me/highorder.scm:42:15>
> 1+
#<procedure:...me/highorder.scm:42:15>
> (1+ 7)
8
> ((1+ 7))
[image] [image] application: not a procedure;
 expected a procedure that can be applied to arguments
  given: 8
  arguments...: [none]
> ((n+ 1) 7)
8
> (+ 1 7)
8
> (n+ 1)
#<procedure:...me/highorder.scm:42:15>
> ((n+ 1) 7)
8
> 
> 2*
#<procedure:...me/highorder.scm:47:2>
> (2* 3)
6.009999999999849
> (repeated 1+ 5)
#<procedure:...me/highorder.scm:52:2>
> ((repeated 1+ 5) 7)
12
>  ((repeated 2* 5) 3)
96.30999999994856
> ((repeated 1+ 5) 7)
12
>  ((repeated 2* 5) 3)
96.30999999994856
> ((repeated 1+ 5) 7)
12
>  ((repeated 2* 5) 3)
96.30999999994856
> (derive-n cos 2 0.001)
#<procedure:...me/highorder.scm:47:2>
> ((derive-n cos 2 0.001) 0)
-0.9999994167175785
> ((derive-n cos 4 0.001) 0)
0.9997558336749535
> ((derive-n cos 4 0.001) 0)
[image] [image] derive: arity mismatch;
 the expected number of arguments does not match the given number
  expected: 2
  given: 1
> ((derive-n cos 4 0.001) 0)
[image] [image] derive: arity mismatch;
 the expected number of arguments does not match the given number
  expected: 2
  given: 1
> ((derive-n cos 4 0.001) 0)
0.9997558336749535
> ((derive-n cos 4 0.001) 0)
[image] [image] derive: arity mismatch;
 the expected number of arguments does not match the given number
  expected: 2
  given: 1
> ((derive-n cos 4 0.001) 0)
[image] [image] +: contract violation
  expected: number?
  given: #<procedure:cos>
  argument position: 1st