He gives this example:

  real, dimension(5) :: a = [ 2, 4, 6, 8, 10 ]
  integer, dimension(2) :: i = [ 2, 4 ]

  print *, a(i)   ! prints 4. 8.

In APL the same is:

    a← 2 4 6 8 10
    a[2 4]
  4 8