Learning Haskell with Chess
Revision as of 09:05, 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 http://www.steffen-mazanek.de/dateien/projekte/hsChess.zip.
@German Haskellers: You may also have a look at the tex-files used in our student exercises, http://www.steffen-mazanek.de/dateien/projekte/hsChess-teaching-german.zip.
1 Exercise 1 - data types
1.1 Learning targets
- recapitulate Haskell types (keywords andtype, product and sum types)data
- Helium: equality and show functions (pattern matching)
- Haskell: type classes (,Show,Eq)deriving
- list handling (boards will be represented by lists of lists)
- Define data types that represent boards (), squares (Board), positions (Square), pieces (Pos, supported byPieceandPieceColor) and game states (PieceType).State
- Helium: Implement suited eq and show functions.
- Haskell: Define/derive instances of andShowEq
- 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, ...prettyBoard::Board->String
- Define the initial board (), testinitialBoard::BoardwithprettyBoard.initialBoard
- Implement a simple evaluation function as the difference of material on board, for this purpose define a functionevalBoard::Board->Intthat maps pieces to their values (pawn->1, knight and bishop->3, queen->9, rook->5, king->"infinity"=1000).valuePiece
2 Exercise 2 - move generator
2.1 Learning targets
- list comprehension
- stepwise refinement
3 Exercise 3 - gametree generation and minimax algorithm
3.1 Learning targets
- break code in modules
- recursive data structures -> recursive algorithms
- Define a data type that represents a game tree ().GameTree
- 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.play::Gametree->Int
- Implement the function , that choses the (best) next state.doMove::State->State