Haskell from C: Where are the for Loops?

In modern Fortran you don't need a loop either. The code to compute the norm of a vector of a billion integers starting with zero is

   program main
   implicit none
   integer         , parameter   :: n = 10**9
   double precision, allocatable :: x(:)
   integer                       :: i
   allocate (x(n))
   forall (i=1:n) x(i) = dble(i-1)
   print*,sqrt(sum(x**2))
   end program main