Personal tools

Learning Haskell with Chess

From HaskellWiki

(Difference between revisions)
Jump to: navigation, search
(Wikifying markup)

Revision as of 08:28, 19 March 2007

This page is about learning Haskell using the board game Chess as a running example. The complete code can be found at


1 Exercise 1 - data types

1.1 Learning targets

  • recapitulate Haskell types (keywords type and data, product and sum types)
    • Helium: define equality functions (pattern matching)
    • Haskell: define instances of type classes Show, Eq
  • pretty printing

1.2 Tasks

  • Define data types that represent boards (
    ), squares (
    ), positions (
    ), pieces (
    ) and game states (
  • Helium: Implement suited eq-functions.
  • Implement a function
    , that transforms a board into a clearly arranged string representation (human readable :-)). Support this function with auxiliary functions that pretty print pieces, squares, ...
  • Define the initial board (
    ), test prettyBoard with initialBoard.
  • Implement a simple evaluation function
    as the difference of material on board (values: Pawn->1, Knight and Bishop->3, Queen->9, Rook->6, King->"infinity"=1000).

2 Exercise 2 - move generator

2.1 Learning targets

  • list comprehension
  • stepwise refinement

2.2 Tasks

3 Exercise 3 - gametree generation and minimax algorithm

3.1 Learning targets

  • break code in modules
  • complexity
  • recursive data structures -> recursive algorithms

3.2 Tasks

  • Define a data type that represents a game tree (
  • Roughly estimate the number of nodes of the gametree with depth 4.
  • Define a function
    , that computes the value of a given game tree using the minimax Algorithm.
  • Implement the function
    , that choses the (best) next state.