Hangman

Instructions

Implement the logic of the hangman game using functional reactive programming.

Hangman is a simple word guessing game.

Functional Reactive Programming is a way to write interactive programs. It differs from the usual perspective in that instead of saying "when the button is pressed increment the counter", you write "the value of the counter is the sum of the number of times the button is pressed."

Implement the basic logic behind hangman using functional reactive programming. You'll need to install an FRP library for this, this will be described in the language/track specific files of the exercise.

New approach to the exercise

Please ignore the part regarding an FRP library, a third party library is not required for this exercise. This exercise focuses on event-driven programming using callbacks and Tcl's event loop.

You are required to construct a TCP server and a domain-specific protocol. This server is launched with the word to guess. The test script implements the client that sends commands to the server.

Domain-specific protocol

The protocol commands to implement are:

• STATUS to return the current state of the game. The response will be a three-elememt list:
  1. the number of bad guesses remaining,
  2. the word masked with underscores for unguessed letters, and
  3. a status field (one of "ongoing", "win" or "lose")
• GUESS x where x is a letter to guess. The server will respond with the status list after each guess.
• SHUTDOWN to remotely shutdown the server. The server will otherwise exit after a win or loss.

The server should be able to handle these commands case-insensitively.

What port does the server use?

Start your server using port number 0: Tcl will find an unused port, so we don't have to hardcode a port number in the test script. All interpreters running in a process (including threads) share the same environment, so the server can communicate its port back to the test script using the global env array. There's an example in the initial hangman.tcl file.

Hints

You'll need these Tcl commands: socket, fileevent, vwait.

This example socket program can get you started.