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Frontmatter

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Author 1
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using Chess
644 ms
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126 μs

White to move

Castle rights: KQkq

Open in lichess

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startboard()
72.3 μs
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domove(startboard(), "e4") |> moves
89.1 ms
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using PlutoUI
142 ms
1
@bind tick Slider(1:length(xs); show_value=true)
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241 ms

Black to move

Castle rights: KQkq

Open in lichess

b = xs[tick]
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20.3 μs
16
pieces(xs[tick], BLACK) |> squarecount
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13.2 ms
16
pieces(xs[tick], WHITE) |> squarecount
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25.0 μs
if ischeckmate(b)
md" $(!sidetomove(b)) wins"
elseif isstalemate(b)
"stalemate"
end
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349 ms
Base.:(!)(p::PieceColor) = p === BLACK ? WHITE : BLACK
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450 μs
xs = try_until_result(random_game)
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40.1 ms

Black to move

Open in lichess

x = try_until_result(random_result)
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48.8 ms
true
ischeckmate(x)
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14.6 μs
false
isstalemate(x)
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17.3 μs
random_result (generic function with 1 method)
function random_result()
board = startboard()
while (next_moves = moves(board); !isempty(next_moves))
choice = rand(next_moves)
board = domove(board, choice)
end
board
end
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674 μs
random_game (generic function with 1 method)
function random_game()
result = []
board = startboard()
while (next_moves = moves(board); !isempty(next_moves))
choice = rand(next_moves)
board = domove(board, choice)
push!(result, board)
end
result
end
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724 μs
try_until_result (generic function with 1 method)
function try_until_result(f::Function, args...)
try
f(args...)
catch
try_until_result(f, args...)
end
end
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602 μs

Chess move input

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189 μs
islegal (generic function with 1 method)
islegal(b::Board, m::Move) = m ∈ moves(b)
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449 μs

Black to move

Open in lichess

your_move_board = try_until_result(random_game)[end-20]
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9.8 ms

Make a move!

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185 μs
abcdefgh87654321
@bind next_move_raw board_input(your_move_board)
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51.7 ms
missing
next_move_raw
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11.6 μs
squarefromstring (generic function with 1 method)
s = squarefromstring
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13.1 μs
Error message

MethodError: no method matching getindex(::Missing, ::String)

Stack trace

Here is what happened, the most recent locations are first:

  1. from This cell: line 1
    next_move = Move(s(next_move_raw["from"]), s(next_move_raw["to"]))
next_move = Move(s(next_move_raw["from"]), s(next_move_raw["to"]))
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---
Error message

Another cell defining next_move contains errors.

islegal(your_move_board, next_move)
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---
Error message

Another cell defining next_move contains errors.

Don't panic!
domove(your_move_board, next_move)
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---
using HypertextLiteral
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2.9 ms
board_input (generic function with 2 methods)
board_input(b=startboard()) = @htl("""
<div>

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/cm-chessboard@3.10.6/styles/cm-chessboard.css"/>

<script id="this">
const div = currentScript.parentElement

const {INPUT_EVENT_TYPE, COLOR, Chessboard} = await import("https://cdn.jsdelivr.net/npm/cm-chessboard@3.10.6/src/cm-chessboard/Chessboard.js")

function inputHandler(event) {
if (event.type === INPUT_EVENT_TYPE.moveDone) {
const move = {from: event.squareFrom, to: event.squareTo}
div.value = move
div.dispatchEvent(new CustomEvent("input"))
} else {
return true
}
}
const board_div = html`<div id="board" style="max-width: 300px;">
</div>`
const board = new Chessboard(board_div, {
position: $(repr(fen(b))),
sprite: {url: "https://cdn.jsdelivr.net/npm/cm-chessboard@3.10.6/assets/images/chessboard-sprite-staunty.svg"},
orientation: COLOR.white
})
board.enableMoveInput(inputHandler, COLOR.white)
return board_div
</script>
</div>
""")
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473 ms

Let's play a game

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200 μs
board = Ref(startboard())
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30.0 μs
abcdefgh87654321
@initially missing @bind move_raw f(move_raw)
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29.6 ms
f (generic function with 1 method)
function f(move_raw)
if move_raw !== missing
move = Move(s(move_raw["from"]), s(move_raw["to"]))
if islegal(board[], move)
# do your move for white
board[] = domove(board[], move)
# do random move for black
board[] = domove(board[], rand(moves(board[])))
end
end
board_input(board[])
end
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926 μs
intially_function (generic function with 1 method)
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8.8 ms