208 lines
No EOL
8.3 KiB
C++
208 lines
No EOL
8.3 KiB
C++
// © 2025 A.M. Rowsell <amr@frzn.dev>
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this
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// file, You can obtain one at http://mozilla.org/MPL/2.0/.
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// This Source Code Form is "Incompatible With Secondary Licenses", as
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// defined by the Mozilla Public License, v. 2.0.
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#include "Piece.hpp"
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Piece::~Piece() {
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return;
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}
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// because the Piece class is instantiated in another class using
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// unique_ptr, non-pure virtual functions apparently *must*
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// have definitions, or the linker freaks out
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// so this is just a stub that does nothing. it doesn't matter
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// because only the derived class versions should be called.
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std::vector<Move> Piece::getLegalMoves(const Square &from, const Board &board) const {
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std::vector<Move> moveList;
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return moveList;
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}
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std::vector<Move> King::getLegalMoves(const Square &from, const Board &board) const {
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std::vector<Move> moveList;
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const int directions[8][2] = {
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{-1, 0}, // Up
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{-1, -1}, // up-left
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{-1, 1}, // up-right
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{1, 0}, // Down
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{1, -1}, // down-left
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{1, 1}, // down-right
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{0, -1}, // Left
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{0, 1} // Right
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};
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for(auto &dir : directions) {
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// establish r/f for square to check
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int r = from.rank + dir[0];
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int f = from.file + dir[1];
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if(r >= 0 && r < 8 && f >= 0 && f < 8) {
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const auto &target = board.boardGrid[r][f]; // examine the target square
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auto ra = static_cast<Rank>(r);
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auto fi = static_cast<File>(f);
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Square targetSquare = {ra, fi};
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if(!target) { // if square is empty (NULL)
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moveList.push_back({from, targetSquare}); // then it's potentially a legal move
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} else if(target && target->getColour() != this->getColour()) { // if it's occupied with a piece of opposite colour
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moveList.push_back({from, targetSquare}); // then again it's potentially legal
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break;
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} else {
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// otherwise it's one of our pieces
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break;
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}
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}
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}
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// How to check for check:
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// go through moveList.to, then check all directions to see if an enemy piece is threatening
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// If a piece of opposite colour is detected:
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// - Determine the piece type
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// - Determine the direction we are looking at (diagonal or not)
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// - If that piece can attack in that direction, it would be check, so remove this move from moveList
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for(auto &moves : moveList) {
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Square startSquare = moves.to; // get the potential move to square
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for(auto &dir : directions) { // now go through all directions
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int r = startSquare.rank + dir[0];
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int f = startSquare.file + dir[1];
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bool diagonal = (abs(dir[0]) + abs(dir[1]) == 2) ? 1 : 0; // check if diagonal
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while(r >= 0 && r < 8 && f >= 0 && f < 8) {
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auto &target = board.boardGrid[r][f]; // check what's at the square we're examining
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if(target && target->getColour() != this->getColour()) { // is it occupied & an enemy?
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if((target->getPieceType() == QUEEN || target->getPieceType() == BISHOP) && diagonal) {
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// we are being attacked diagonally on this square, so remove it
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//moves.to.rank = 255; moves.to.file = 255; // mark as invalid???
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}
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}
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}
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}
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}
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return moveList;
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}
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std::vector<Move> Rook::getLegalMoves(const Square &from, const Board &board) const {
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std::vector<Move> moveList;
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const int directions[4][2] = {
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{-1, 0}, // Up
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{1, 0}, // Down
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{0, -1}, // Left
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{0, 1} // Right
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};
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for(auto& dir : directions) {
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int r = from.rank + dir[0];
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int f = from.file + dir[1];
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while(r >= 0 && r < 8 && f >= 0 && f < 8) {
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const auto& target = board.boardGrid[r][f];
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auto ra = static_cast<Rank>(r);
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auto fi = static_cast<File>(f);
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Square targetSquare = {ra, fi};
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if(!target) {
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moveList.push_back({from, targetSquare});
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} else if(target && target->getColour() != this->getColour()) {
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moveList.push_back({from, targetSquare});
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break;
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} else
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break;
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r += dir[0];
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f += dir[1];
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}
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}
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return moveList;
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}
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std::vector<Move> Queen::getLegalMoves(const Square &from, const Board &board) const {
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std::vector<Move> moveList;
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return moveList;
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}
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std::vector<Move> Knight::getLegalMoves(const Square &from, const Board &board) const {
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std::vector<Move> moveList;
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return moveList;
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}
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std::vector<Move> Bishop::getLegalMoves(const Square &from, const Board &board) const {
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std::vector<Move> moveList;
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return moveList;
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}
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std::vector<Move> Pawn::getLegalMoves(const Square &from, const Board &board) const {
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std::vector<Move> moveList;
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const int directions[2][4][2] = {
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{
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// black
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{-1, 0}, // Up
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{-2, 0}, // 2up first move
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{-1, 1}, // attack to right
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{-1, -1} // attack to left
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},
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{
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// white
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{1, 0}, // down
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{2, 0}, // 2down first move
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{1, 1}, // attack to right
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{1, -1} // attack to left
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}
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};
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if(this->getColour() == PIECE_BLACK) {
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// go through black options
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for(auto &dir : directions[0]) {
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int r = from.rank + dir[0];
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int f = from.file + dir[1];
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if(r >= 0 && r < 8 && f >= 0 && f < 8) { // no need for a while loop as we only have finite moves in limited directions
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const auto& target = board.boardGrid[r][f];
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auto ra = static_cast<Rank>(r);
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auto fi = static_cast<File>(f);
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Square targetSquare = {ra, fi};
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if(dir[0] == -2 && !this->checkIfMoved()) {
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// then 2 is potentially legal
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if(!target && !(board.boardGrid[r + 1][f])) // check both squares for pieces of any colour
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moveList.push_back({from, targetSquare});
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else
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continue;
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} else if(abs(dir[1]) == 1) { // attempted capture (diagonal)
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if(target && target->getColour() != this->getColour()) {
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// legal capture
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moveList.push_back({from, targetSquare});
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} else
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continue;
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} else { // normal one square forward
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if(!target)
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moveList.push_back({from, targetSquare});
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}
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// now check if we are on 8th rank, for promotion
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}
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}
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} else if(this->getColour() == PIECE_WHITE) {
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for(auto &dir : directions[1]) {
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// go through white options
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int r = from.rank + dir[0];
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int f = from.file + dir[1];
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if(r >= 0 && r < 8 && f >= 0 && f < 8) { // no need for a while loop as we only have finite moves in limited directions
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const auto& target = board.boardGrid[r][f];
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auto ra = static_cast<Rank>(r);
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auto fi = static_cast<File>(f);
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Square targetSquare = {ra, fi};
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if(dir[0] == 2 && !this->checkIfMoved()) {
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// then 2 is potentially legal
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if(!target && !(board.boardGrid[r - 1][f]))
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moveList.push_back({from, targetSquare});
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else
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continue;
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} else if(abs(dir[1]) == 1) { // attempted capture (diagonal)
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if(target && target->getColour() != this->getColour()) { // can only move there if it's a capture
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// legal capture
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moveList.push_back({from, targetSquare});
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} else
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continue;
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} else { // normal one square forward
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if(!target)
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moveList.push_back({from, targetSquare});
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}
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// now check if we are on 8th rank, for promotion
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}
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}
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}
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return moveList;
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} |