FsharpHanoi

A small F# console sample that solves the Tower of Hanoi puzzle using the State monad from FSharpPlus. Each recursive move is pushed onto a state-tracked list via monad { ... } computation expressions, and the final move sequence is printed to the console.

This is a legacy learning sample (last updated in 2020) targeting .NET Framework 4.5.1 with the classic .fsproj / packages.config project format.

How It Works

• hanoi src bare dst height recursively builds the move sequence inside State<Step list, unit>
• Each move is recorded as a Step record (Src, Dst, Height) using modify
• State.exec runs the computation against an empty list and yields the ordered move list
• main solves a 3-disk puzzle from "Left" to "Right" and prints the result with printfn "%A"

Requirements

• .NET Framework 4.5.1 (or Mono) with F# tooling — Visual Studio / Visual Studio for Mac era
• NuGet packages (via packages.config): FSharp.Core 4.7.2, FSharpPlus 1.1.1, System.ValueTuple 4.4.0

Usage

Open FsharpHanoi.sln in Visual Studio, restore NuGet packages, then build and run. The program prints the move list for a 3-disk Tower of Hanoi. Change the argument of result in Program.fs to solve for a different disk count.

Project Structure

FsharpHanoi.sln          # Solution file
FsharpHanoi/
  Program.fs             # Hanoi solver using FSharpPlus State monad
  FsharpHanoi.fsproj     # Legacy-format F# project (net451)
  packages.config        # NuGet package pins