Learning Haskell with Chess
This page is about learning Haskell using the board game Chess as a running example. The complete code can be found at http://www.steffen-mazanek.de/dateien/projekte/hsChess.zip.
Exercise 1 - data types
- 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
- Define data types that represent boards (
Board), squares (
Square), positions (
Pos), pieces (
Piece) and game states (
- Helium: Implement suited eq-functions.
- Implement a function
prettyBoard::Board->String, 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 (
initialBoard::Board), test prettyBoard with initialBoard.
- Implement a simple evaluation function
evalBoard::Board->Intas the difference of material on board (values: Pawn->1, Knight and Bishop->3, Queen->9, Rook->6, King->"infinity"=1000).
Exercise 2 - move generator
- list comprehension
- stepwise refinement
Exercise 3 - gametree generation and minimax algorithm
- break code in modules
- recursive data structures -> recursive algorithms
- Define a data type that represents a game tree (
- Roughly estimate the number of nodes of the gametree with depth 4.
- Define a function
play::Gametree->Int, that computes the value of a given game tree using the minimax Algorithm.
- Implement the function
doMove::State->State, that choses the (best) next state.