gearsco.de
A chess library for Gleam
Document generator script
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dev/starfish_dev.gleam
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dev/starfish_dev.gleam
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//// Code generation for various parts of the engine
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import gleam/int
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import simplifile as file
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import starfish/internal/board
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const generated_file_path = "src/starfish/internal/generated.gleam"
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const piece_count = 12
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pub fn main() {
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let imports =
···
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file.write(to: generated_file_path, contents: generated_code)
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}
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/// 60 bits is the highest we can go on Erlang where bitwise operations are fast,
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/// so we limit hashes to 60 bits to ensure computing hashes is as fast as possible.
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const max_60_bit_int = 576_460_752_303_423_500
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const piece_count = 12
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fn generate_hash_data() -> String {
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let function_head =
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"pub fn hash_for_piece(piece: board.Piece, colour: board.Colour, position: Int) -> Int {
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case piece, colour, position {"
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let length = piece_count * board.size
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let hash_for_piece = generate_hash_data_loop(function_head, 0, length)
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// Generate a random hash to indicate that it's black's turn to move
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let black_to_move =
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"pub const black_to_move_hash = 0x"
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<> int.to_base16(int.random(max_60_bit_int))
···
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False -> {
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let position = generated / piece_count
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let position = case position == board.size - 1 {
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// The last square needs to be a catch-all to ensure the `case` expression
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// compiles.
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True -> "_"
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False -> int.to_string(position)
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}
···
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<> ", "
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<> position
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<> " -> 0x"
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// Generate a random 60-bit hash for this combination of piece and position
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<> int.to_base16(int.random(max_60_bit_int))
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generate_hash_data_loop(acc, generated + 1, length)
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}