Solution of Tower of Hanoi problem using F#

TowerOfHanoi.fs

let rec TowerOfHanoi fromPole destPole tempPole disks =
    if disks > 0 then
        TowerOfHanoi fromPole tempPole destPole (disks - 1)
        printfn "Moving from %c to %c" fromPole destPole
        TowerOfHanoi tempPole destPole fromPole (disks - 1)
        
TowerOfHanoi '1' '2' '3' '4'

Tower Of Hanoi Problem using F

The Tower of Hanoi puzzle was invented by the French mathematician Edouard Lucas in 1883. We are given a tower of eight disks (initially four in the applet below), initially stacked in increasing size on one of three pegs. The objective is to transfer the entire tower to one of the other pegs (the rightmost one in the applet below), moving only one disk at a time and never a larger one onto a smaller.

Recursive solution
Let call the three pegs Src (Source), Aux (Auxiliary) and Dst (Destination). To better understand and appreciate the following solution you should try solving the puzzle for small number of disks, say, 2,3, and, perhaps, 4. However one solves the problem, sooner or later the bottom disk will have to be moved from Src to Dst. At this point in time all the remaining disks will have to be stacked in decreasing size order on Aux. After moving the bottom disk from Src to Dst these disks will have to be moved from Aux to Dst. Therefore, for a given number N of disks, the problem appears to be solved if we know how to accomplish the following tasks:

Move the top N - 1 disks from Src to Aux (using Dst as an intermediary peg)
Move the bottom disk from Src to Dst
Move N - 1 disks from Aux to Dst (using Src as an intermediary peg)

Assume there is a function Solve with four arguments - number of disks and three pegs (source, intermediary and destination - in this order). Then the body of the function might look like

Solve(N, Src, Aux, Dst)
    if N is 0 
      exit
    else
      Solve(N - 1, Src, Dst, Aux)
      Move from Src to Dst
      Solve(N - 1, Aux, Src, Dst)

Output

Moving from 1 to 3
Moving from 1 to 2
Moving from 3 to 2
Moving from 1 to 3
Moving from 2 to 1
Moving from 2 to 3
Moving from 1 to 3
Moving from 1 to 2
Moving from 3 to 2
Moving from 3 to 1
Moving from 2 to 1
Moving from 3 to 2
Moving from 1 to 3
Moving from 1 to 2
Moving from 3 to 2

More information about this problem can be found at:
Tower of Hanoi
Tower of Hanoi

Great write-up! Solution is a lot more readable than some of the other F# solutions out there.

A small correction: printf in line 4 should be printfn.

Thank you @isocolon I updated code as you suggested.