Fix algebraicToLocation and added getPiece function
This commit is contained in:
parent
4410adb40b
commit
d52c1e3526
|
@ -13,12 +13,17 @@
|
|||
# limitations under the License.
|
||||
import ../util/matrix
|
||||
|
||||
export matrix
|
||||
|
||||
import std/strutils
|
||||
import std/strformat
|
||||
|
||||
|
||||
type
|
||||
Location = tuple[row, col: int]
|
||||
Pieces = tuple[king: Location, queen: Location, rooks: array[2, Location],
|
||||
bishops: array[2, Location], knights: array[2, Location],
|
||||
pawns: array[8, Location]]
|
||||
PieceColor* = enum
|
||||
None = 0,
|
||||
White,
|
||||
|
@ -36,10 +41,10 @@ type
|
|||
kind*: PieceKind
|
||||
Position* = object
|
||||
piece*: Piece
|
||||
location*: tuple[row, col: int]
|
||||
location*: Location
|
||||
ChessBoard* = ref object
|
||||
## A chess board object
|
||||
grid: Matrix[Piece]
|
||||
grid*: Matrix[Piece]
|
||||
# Currently active color
|
||||
turn: PieceColor
|
||||
# Number of half moves since
|
||||
|
@ -55,6 +60,11 @@ type
|
|||
# If en passant is not possible, both the row and
|
||||
# column of the position will be set to -1
|
||||
enPassantSquare: Position
|
||||
# Locations of all pieces
|
||||
pieces: tuple[white: Pieces, black: Pieces]
|
||||
# Locations of all attacked squares
|
||||
attacked: tuple[white: seq[Location], black: seq[Location]]
|
||||
|
||||
|
||||
# Initialized only once, copied every time
|
||||
var empty: seq[Piece] = @[]
|
||||
|
@ -62,12 +72,46 @@ for _ in countup(0, 63):
|
|||
empty.add(Piece(kind: Empty, color: None))
|
||||
|
||||
|
||||
proc algebraicToPosition(s: string): tuple[row, col: int] {.inline.} =
|
||||
proc algebraicToPosition(s: string): Location {.inline.} =
|
||||
## Converts a square location from algebraic
|
||||
## notation to its corresponding row and column
|
||||
## in the chess grid (0 indexed)
|
||||
assert len(s) == 2
|
||||
result = (int(uint8(s[0]) - (uint8('a') - 1)), int(uint8(s[1]) - uint8('0')))
|
||||
if len(s) != 2:
|
||||
raise newException(ValueError, "algebraic position must be of length 2")
|
||||
var s = s.toLowerAscii()
|
||||
|
||||
if s[0] notin 'a'..'h':
|
||||
raise newException(ValueError, &"algebraic position has invalid first character ('{s[0]}')")
|
||||
if s[1] notin '1'..'8':
|
||||
raise newException(ValueError, &"algebraic position has invalid second character ('{s[1]}')")
|
||||
let file = int(uint8(s[0]) - uint8('a'))
|
||||
var rank: int
|
||||
case s[1]:
|
||||
of '1':
|
||||
rank = 7
|
||||
of '2':
|
||||
rank = 6
|
||||
of '3':
|
||||
rank = 5
|
||||
of '4':
|
||||
rank = 4
|
||||
of '5':
|
||||
rank = 3
|
||||
of '6':
|
||||
rank = 2
|
||||
of '7':
|
||||
rank = 1
|
||||
of '8':
|
||||
rank = 0
|
||||
else:
|
||||
discard
|
||||
return (rank, file)
|
||||
|
||||
proc getPiece*(self: ChessBoard, square: string): Piece =
|
||||
## Gets the piece on the given square
|
||||
## in algebraic notation
|
||||
let loc = square.algebraicToPosition()
|
||||
return self.grid[loc.row, loc.col]
|
||||
|
||||
|
||||
proc `$`*(self: ChessBoard): string =
|
||||
|
@ -84,12 +128,33 @@ proc `$`*(self: ChessBoard): string =
|
|||
result &= "\n- - - - - - - -"
|
||||
|
||||
|
||||
proc newChessboard: ChessBoard =
|
||||
## Returns a new, empty chessboard
|
||||
new(result)
|
||||
# Initialize all positions to a known default state.
|
||||
# This is useful in newChessBoardFromFEN
|
||||
result.pieces.black.king = (-1, -1)
|
||||
result.pieces.white.king = (-1, -1)
|
||||
result.pieces.black.queen = (-1, -1)
|
||||
result.pieces.white.queen = (-1, -1)
|
||||
result.pieces.black.rooks = [(-1, -1), (-1, -1)]
|
||||
result.pieces.white.rooks = [(-1, -1), (-1, -1)]
|
||||
result.pieces.black.bishops = [(-1, -1), (-1, -1)]
|
||||
result.pieces.white.bishops = [(-1, -1), (-1, -1)]
|
||||
result.pieces.black.knights = [(-1, -1), (-1, -1)]
|
||||
result.pieces.white.knights = [(-1, -1), (-1, -1)]
|
||||
result.pieces.black.pawns = [(-1, -1), (-1, -1), (-1, -1), (-1, -1), (-1, -1), (-1, -1), (-1, -1), (-1, -1)]
|
||||
result.pieces.white.pawns = [(-1, -1), (-1, -1), (-1, -1), (-1, -1), (-1, -1), (-1, -1), (-1, -1), (-1, -1)]
|
||||
# Turns our flat sequence into an 8x8 grid
|
||||
result.grid = newMatrixFromSeq[Piece](empty, (8, 8))
|
||||
result.attacked = (@[], @[])
|
||||
result.enPassantSquare = Position(piece: Piece(kind: Empty, color: None), location: (-1, -1))
|
||||
|
||||
|
||||
proc newChessboardFromFEN*(state: string): ChessBoard =
|
||||
## Initializes a chessboard with the
|
||||
## state encoded by the given FEN string
|
||||
new(result)
|
||||
# Turns our flat sequence into an 8x8 grid
|
||||
result.grid = newMatrixFromSeq[Piece](empty, (8, 8))
|
||||
result = newChessboard()
|
||||
var
|
||||
# Current location in the grid
|
||||
row = 0
|
||||
|
@ -98,6 +163,8 @@ proc newChessboardFromFEN*(state: string): ChessBoard =
|
|||
section = 0
|
||||
# Current index into the FEN string
|
||||
index = 0
|
||||
# Temporary variable to store the piece
|
||||
piece: Piece
|
||||
# See https://en.wikipedia.org/wiki/Forsyth%E2%80%93Edwards_Notation
|
||||
while index <= state.high():
|
||||
var c = state[index]
|
||||
|
@ -110,13 +177,82 @@ proc newChessboardFromFEN*(state: string): ChessBoard =
|
|||
of 0:
|
||||
# Piece placement data
|
||||
case c.toLowerAscii():
|
||||
# Piece
|
||||
of 'r', 'n', 'b', 'q', 'k', 'p':
|
||||
result.grid[row, column] = Piece(kind: PieceKind(c.toLowerAscii()), color: if c.isUpperAscii(): White else: Black)
|
||||
# We know for a fact these values are in our
|
||||
# enumeration, so all is good
|
||||
{.push.}
|
||||
{.warning[HoleEnumConv]:off.}
|
||||
piece = Piece(kind: PieceKind(c.toLowerAscii()), color: if c.isUpperAscii(): White else: Black)
|
||||
{.pop.}
|
||||
case piece.color:
|
||||
of Black:
|
||||
case piece.kind:
|
||||
of Pawn:
|
||||
# Find first empty slot in the pieces array
|
||||
for i, e in result.pieces.black.pawns:
|
||||
if e == (-1, -1):
|
||||
result.pieces.black.pawns[i] = (row, column)
|
||||
break
|
||||
of Bishop:
|
||||
if result.pieces.black.bishops[0] == (-1, -1):
|
||||
result.pieces.black.bishops[0] = (row, column)
|
||||
else:
|
||||
result.pieces.black.bishops[1] = (row, column)
|
||||
of Knight:
|
||||
if result.pieces.black.knights[0] == (-1, -1):
|
||||
result.pieces.black.knights[0] = (row, column)
|
||||
else:
|
||||
result.pieces.black.knights[1] = (row, column)
|
||||
of Rook:
|
||||
if result.pieces.black.rooks[0] == (-1, -1):
|
||||
result.pieces.black.rooks[0] = (row, column)
|
||||
else:
|
||||
result.pieces.black.rooks[1] = (row, column)
|
||||
of Queen:
|
||||
result.pieces.black.queen = (row, column)
|
||||
of King:
|
||||
result.pieces.black.king = (row, column)
|
||||
else:
|
||||
discard
|
||||
of White:
|
||||
case piece.kind:
|
||||
of Pawn:
|
||||
for i, e in result.pieces.white.pawns:
|
||||
if e == (-1, -1):
|
||||
result.pieces.white.pawns[i] = (row, column)
|
||||
break
|
||||
of Bishop:
|
||||
if result.pieces.white.bishops[0] == (-1, -1):
|
||||
result.pieces.white.bishops[0] = (row, column)
|
||||
else:
|
||||
result.pieces.white.bishops[1] = (row, column)
|
||||
of Knight:
|
||||
if result.pieces.white.knights[0] == (-1, -1):
|
||||
result.pieces.white.knights[0] = (row, column)
|
||||
else:
|
||||
result.pieces.white.knights[1] = (row, column)
|
||||
of Rook:
|
||||
if result.pieces.white.rooks[0] == (-1, -1):
|
||||
result.pieces.white.rooks[0] = (row, column)
|
||||
else:
|
||||
result.pieces.white.rooks[1] = (row, column)
|
||||
of Queen:
|
||||
result.pieces.white.queen = (row, column)
|
||||
of King:
|
||||
result.pieces.white.king = (row, column)
|
||||
else:
|
||||
discard
|
||||
else:
|
||||
discard
|
||||
result.grid[row, column] = piece
|
||||
inc(column)
|
||||
of '/':
|
||||
# Next row
|
||||
inc(row)
|
||||
column = 0
|
||||
of '0'..'9':
|
||||
# Skip x columns
|
||||
let x = int(uint8(c) - uint8('0')) - 1
|
||||
if x > 7:
|
||||
raise newException(ValueError, "invalid skip value (> 8) in FEN string")
|
||||
|
@ -154,7 +290,8 @@ proc newChessboardFromFEN*(state: string): ChessBoard =
|
|||
# En passant target square
|
||||
case c:
|
||||
of '-':
|
||||
result.enPassantSquare.location = (-1, -1)
|
||||
# Field is already uninitialized to the correct state
|
||||
discard
|
||||
else:
|
||||
result.enPassantSquare.location = state[index..index+1].algebraicToPosition()
|
||||
# Just for cleanliness purposes, we fill in the other positional metadata as
|
||||
|
|
|
@ -1,5 +1,10 @@
|
|||
import board
|
||||
|
||||
|
||||
var b = newDefaultChessboard()
|
||||
echo b
|
||||
echo b.getPiece("a2")
|
||||
echo b.getPiece("a7")
|
||||
echo b.getPiece("a1")
|
||||
echo b.getPiece("a8")
|
||||
|
||||
echo newChessboardFromFEN("rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1")[]
|
||||
|
|
Loading…
Reference in New Issue