Difference between revisions of "Learning Haskell with Chess"
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===Learning targets=== |
===Learning targets=== |
||
− | *recapitulate Haskell types (keywords type and data, product and sum types) |
+ | *recapitulate Haskell types (keywords <hask>type</hask> and <hask>data</hask>, product and sum types) |
**Helium: equality and show functions (pattern matching) |
**Helium: equality and show functions (pattern matching) |
||
− | **Haskell: type classes (<hask>Show</hask>, <hask>Eq</hask>, <hask>deriving</hask> |
+ | **Haskell: type classes (<hask>Show</hask>, <hask>Eq</hask>, <hask>deriving</hask>) |
+ | *list handling (boards will be represented by lists of lists) |
||
− | *pretty printing |
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===Tasks=== |
===Tasks=== |
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**Haskell: Define/derive instances of <hask>Show</hask> and <hask>Eq</hask> |
**Haskell: Define/derive instances of <hask>Show</hask> and <hask>Eq</hask> |
||
*Implement a function <hask>prettyBoard::Board->String</hask>, that transforms a board into a clearly arranged string representation (human readable :-)). Support this function with auxiliary functions that pretty print pieces, squares, ... |
*Implement a function <hask>prettyBoard::Board->String</hask>, 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 (<hask>initialBoard::Board</hask>), test prettyBoard with initialBoard. |
+ | *Define the initial board (<hask>initialBoard::Board</hask>), test <hask>prettyBoard</hask> with <hask>initialBoard</hask>. |
− | *Implement a simple evaluation function <hask>evalBoard::Board->Int</hask> as the difference of material on board |
+ | *Implement a simple evaluation function <hask>evalBoard::Board->Int</hask> as the difference of material on board, for this purpose define a function <hask>valuePiece</hask> that maps pieces to their values (pawn->1, knight and bishop->3, queen->9, rook->5, king->"infinity"=1000). |
==Exercise 2 - move generator== |
==Exercise 2 - move generator== |
Revision as of 08:39, 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.
Exercise 1 - data types
Learning targets
- recapitulate Haskell types (keywords
type
anddata
, product and sum types)- Helium: equality and show functions (pattern matching)
- Haskell: type classes (
Show
,Eq
,deriving
)
- list handling (boards will be represented by lists of lists)
Tasks
- Define data types that represent boards (
Board
), squares (Square
), positions (Pos
), pieces (Piece
, supported byPieceColor
andPieceType
) and game states (State
).- Helium: Implement suited eq and show functions.
- Haskell: Define/derive instances of
Show
andEq
- 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
), testprettyBoard
withinitialBoard
. - Implement a simple evaluation function
evalBoard::Board->Int
as the difference of material on board, for this purpose define a functionvaluePiece
that maps pieces to their values (pawn->1, knight and bishop->3, queen->9, rook->5, king->"infinity"=1000).
Exercise 2 - move generator
Learning targets
- list comprehension
- stepwise refinement
Tasks
Exercise 3 - gametree generation and minimax algorithm
Learning targets
- break code in modules
- complexity
- recursive data structures -> recursive algorithms
Tasks
- 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
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.