Add pawn promotion notation

src/constants.h

@@ -100,5 +100,11 @@ const std::array<char, 13> CHESS_CHARS = {
 	'P', 'N', 'B', 'R', 'Q', 'K',
 	'p', 'n', 'b', 'r', 'q', 'k'
 };
+// This returns the same letter weather the team is black or white
+const std::array<std::string, 13> CHESS_CHARS_INSENSITIVE = {
+	" ",
+	"P", "N", "B", "R", "Q", "K",
+	"P", "N", "B", "R", "Q", "K"
+};
 #endif
 

src/functions.cpp

@@ -271,12 +271,17 @@ std::string to_notation(int move, std::array<PieceType, 120> *board){
 	
 	auto moved_board = dumb_move(move, *board);
 	int from = get_from_sq(move);
+	PieceType piecetype = (*board)[from];	
 	std::string from_string = POSITION_STRING[from];
 	int to = get_to_sq(move);
 	int captured_piece = get_captured_pc(move);
+	int promoting_to = get_promoted_to_pc(move);
+	// Blank if not pawn
+	// file if pawn and capture move
+	std::string pawn_file = "";
 	// Blank if pawn
 	// otherwise N/B/R/Q/K corresponding to each piece
-	// same black and white
+	// same for black and white
 	std::string piece_character = "";
 	// Blank if not a capture
 	// x if a capture move
@@ -293,38 +298,22 @@ std::string to_notation(int move, std::array<PieceType, 120> *board){
 	// includes rank (1-8) if pieces have same file
 	// includes both (f)(r) if 2+ identical piece can move to the to square
 	std::string disambig = "";
-	PieceType piecetype = (*board)[from];	
+	// Blank if not a pawn promotion move.
+	// Otherwise is equal to "=P/N/B/R/Q".
+	std::stringstream promotion;
 	auto other_pieces = is_white(piecetype)?Pieces::BLACK:Pieces::WHITE;
 
-	switch(piecetype){
-		case PieceType::W_KNIGHT:
-		case PieceType::B_KNIGHT:
-			piece_character = "N";
-			break;
-		case PieceType::W_BISHOP:
-		case PieceType::B_BISHOP:
-			piece_character = "B";
-			break;
-		case PieceType::W_ROOK:
-		case PieceType::B_ROOK:
-			piece_character = "R";
-			break;
-		case PieceType::W_QUEEN:
-		case PieceType::B_QUEEN:
-			piece_character = "Q";
-			break;
-		case PieceType::W_KING:
-		case PieceType::B_KING:
-			piece_character = "K";
-			break;
-	}
-	if (captured_piece > 0){
+	if (captured_piece != 0){
 		capture_character = "x";
-		// If is a pawn
-		if (piece_character == ""){
-			ss << from_string[0];
+		if (piecetype == PieceType::W_PAWN ||
+			piecetype == PieceType::B_PAWN){
+			pawn_file = POSITION_STRING[from][0];
 		}
 	}
+	if (piecetype != PieceType::W_PAWN &&
+		piecetype != PieceType::B_PAWN){
+			piece_character = CHESS_CHARS_INSENSITIVE[piecetype];
+	}
 	if (get_en_pass_flag(move) == 1){
 		en_passant = "e.p.";
 	}
@@ -374,11 +363,15 @@ std::string to_notation(int move, std::array<PieceType, 120> *board){
 			disambig = POSITION_STRING[from];
 		}
 	}
+
+	if (promoting_to != PieceType::NONE){
+		promotion << "=" << CHESS_CHARS_INSENSITIVE[promoting_to];
+	}
 	// end of checking for multiple pieces
 	if (get_castle_flag(move) == 1){
 		return to-from<0 ? "O-O-O" : "O-O";
 	} else {
-		ss << piece_character << disambig << capture_character << POSITION_STRING[to] << en_passant << check;
+		ss << pawn_file << piece_character << disambig << capture_character << POSITION_STRING[to] << en_passant << promotion.str() << check;
 	}
 	return ss.str();
 }

tests/main.cpp

@@ -220,6 +220,8 @@ TEST_CASE("Test that algebraic notation conversion is working.", "[to_notation]"
 	auto king_castle_moves = get_all_moves(CASTLING_POS, CASTLE_BOARD, true, 0, 0xF);
 	auto king_bcastle_moves = get_all_moves(BCASTLING_POS, CASTLE_BOARD, true, 0, 0xF);
 	auto en_passant_moves = get_all_moves(EN_PASSANT_TEST_POS, EN_PASSANT_TEST_BOARD, true, EN_PASSANT_SQUARE, 0);
+	auto pawn_prom_moves = get_all_moves(PROM_PAWN_POS, PROM_PAWN_BOARD);
+	auto bpawn_prom_moves = get_all_moves(PROM_BPAWN_POS, PROM_BPAWN_BOARD);
 
 	CHECK(get_notations(knight_moves, KNIGHT_BLOCKED1_BOARD) == KNIGHT_BLOCKED1_NOTATION);
 	CHECK(get_notations(bishop_moves, BISHOP_BLOCKED1_BOARD) == BISHOP_BLOCKED1_NOTATION);
@@ -229,6 +231,8 @@ TEST_CASE("Test that algebraic notation conversion is working.", "[to_notation]"
 	CHECK(get_notations(king_castle_moves, CASTLE_BOARD) == CASTLING_MOVES_NOTATION);
 	CHECK(get_notations(king_bcastle_moves, CASTLE_BOARD) == BCASTLING_MOVES_NOTATION);
 	CHECK(get_notations(en_passant_moves, EN_PASSANT_TEST_BOARD) == EN_PASSANT_TEST_NOTATION);
+	CHECK(get_notations(pawn_prom_moves, PROM_PAWN_BOARD) == PROM_PAWN_NOTATION);
+	CHECK(get_notations(bpawn_prom_moves, PROM_BPAWN_BOARD) == PROM_BPAWN_NOTATION);
 }
 
 TEST_CASE("Test for disambiguating moves in algebraic notation", "[to_notation]"){

tests/valid_moves.h

@@ -234,6 +234,10 @@ const std::vector<int> PROM_PAWN_PROMS = {
 	W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN,
 	W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN
 };
+const std::vector<std::string> PROM_PAWN_NOTATION = {
+	"gxh8=N","gxh8=B","gxh8=R","gxh8=Q",
+	"gxf8=N","gxf8=B","gxf8=R","gxf8=Q"
+};
 
 // Black pawn promotion
 const int PROM_BPAWN_POS = B2;
@@ -260,6 +264,10 @@ const std::vector<int> PROM_BPAWN_PROMS = {
 	B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN,
 	B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN
 };
+const std::vector<std::string> PROM_BPAWN_NOTATION = {
+	"bxc1=N","bxc1=B","bxc1=R","bxc1=Q",	
+	"bxa1=N","bxa1=B","bxa1=R","bxa1=Q"	
+};
 
 const int NO_EN_PASSANT_TEST_POS = D5;
 const std::array<PieceType, 120> NO_EN_PASSANT_TEST_BOARD = {