client/src/variants/Checkered.js

   1 import { ChessRules, Move, PiPo } from "@/base_rules";
   2
   3 export class CheckeredRules extends ChessRules {
   4
   5   static get Options() {
   6     return Object.assign(
   7       {},
   8       ChessRules.Options,
   9       {
  10         check: [
  11           {
  12             label: "With switch",
  13             defaut: true,
  14             variable: "switch"
  15           }
  16         ]
  17       }
  18     );
  19   }
  20
  21   static AbbreviateOptions(opts) {
  22     return (!opts["switch"] ? "NS" : "");
  23   }
  24
  25   static board2fen(b) {
  26     const checkered_codes = {
  27       p: "s",
  28       q: "t",
  29       r: "u",
  30       b: "c",
  31       n: "o"
  32     };
  33     if (b[0] == "c") return checkered_codes[b[1]];
  34     return ChessRules.board2fen(b);
  35   }
  36
  37   static fen2board(f) {
  38     // Tolerate upper-case versions of checkered pieces (why not?)
  39     const checkered_pieces = {
  40       s: "p",
  41       S: "p",
  42       t: "q",
  43       T: "q",
  44       u: "r",
  45       U: "r",
  46       c: "b",
  47       C: "b",
  48       o: "n",
  49       O: "n"
  50     };
  51     if (Object.keys(checkered_pieces).includes(f))
  52       return "c" + checkered_pieces[f];
  53     return ChessRules.fen2board(f);
  54   }
  55
  56   static get PIECES() {
  57     return ChessRules.PIECES.concat(["s", "t", "u", "c", "o"]);
  58   }
  59
  60   getPpath(b) {
  61     return (b[0] == "c" ? "Checkered/" : "") + b;
  62   }
  63
  64   setOtherVariables(fen) {
  65     super.setOtherVariables(fen);
  66     // Local stack of non-capturing checkered moves:
  67     this.cmoves = [];
  68     const cmove = V.ParseFen(fen).cmove;
  69     if (cmove == "-") this.cmoves.push(null);
  70     else {
  71       this.cmoves.push({
  72         start: ChessRules.SquareToCoords(cmove.substr(0, 2)),
  73         end: ChessRules.SquareToCoords(cmove.substr(2))
  74       });
  75     }
  76     // Stage 1: as Checkered2. Stage 2: checkered pieces are autonomous
  77     const stageInfo = V.ParseFen(fen).stage;
  78     this.stage = parseInt(stageInfo[0], 10);
  79     this.canSwitch = (this.stage == 1 && stageInfo[1] != '-');
  80     this.sideCheckered = (this.stage == 2 ? stageInfo[1] : undefined);
  81   }
  82
  83   static IsGoodFen(fen) {
  84     if (!ChessRules.IsGoodFen(fen)) return false;
  85     const fenParts = fen.split(" ");
  86     if (fenParts.length != 7) return false;
  87     if (fenParts[5] != "-" && !fenParts[5].match(/^([a-h][1-8]){2}$/))
  88       return false;
  89     if (!fenParts[6].match(/^[12][wb-]?$/)) return false;
  90     return true;
  91   }
  92
  93   static IsGoodFlags(flags) {
  94     // 4 for castle + 16 for pawns
  95     return !!flags.match(/^[a-z]{4,4}[01]{16,16}$/);
  96   }
  97
  98   setFlags(fenflags) {
  99     super.setFlags(fenflags); //castleFlags
 100     this.pawnFlags = {
 101       w: [...Array(8)], //pawns can move 2 squares?
 102       b: [...Array(8)]
 103     };
 104     const flags = fenflags.substr(4); //skip first 4 letters, for castle
 105     for (let c of ["w", "b"]) {
 106       for (let i = 0; i < 8; i++)
 107         this.pawnFlags[c][i] = flags.charAt((c == "w" ? 0 : 8) + i) == "1";
 108     }
 109   }
 110
 111   aggregateFlags() {
 112     return [this.castleFlags, this.pawnFlags];
 113   }
 114
 115   disaggregateFlags(flags) {
 116     this.castleFlags = flags[0];
 117     this.pawnFlags = flags[1];
 118   }
 119
 120   getEpSquare(moveOrSquare) {
 121     // At stage 2, all pawns can be captured en-passant
 122     if (
 123       this.stage == 2 ||
 124       typeof moveOrSquare !== "object" ||
 125       (moveOrSquare.appear.length > 0 && moveOrSquare.appear[0].c != 'c')
 126     )
 127       return super.getEpSquare(moveOrSquare);
 128     // Checkered or switch move: no en-passant
 129     return undefined;
 130   }
 131
 132   getCmove(move) {
 133     // No checkered move to undo at stage 2:
 134     if (this.stage == 1 && move.vanish.length == 1 && move.appear[0].c == "c")
 135       return { start: move.start, end: move.end };
 136     return null;
 137   }
 138
 139   canTake([x1, y1], [x2, y2]) {
 140     const color1 = this.getColor(x1, y1);
 141     const color2 = this.getColor(x2, y2);
 142     if (this.stage == 2) {
 143       // Black & White <-- takes --> Checkered
 144       const color1 = this.getColor(x1, y1);
 145       const color2 = this.getColor(x2, y2);
 146       return color1 != color2 && [color1, color2].includes('c');
 147     }
 148     // Checkered aren't captured
 149     return (
 150       color1 != color2 &&
 151       color2 != "c" &&
 152       (color1 != "c" || color2 != this.turn)
 153     );
 154   }
 155
 156   getPotentialMovesFrom([x, y], noswitch) {
 157     let standardMoves = super.getPotentialMovesFrom([x, y]);
 158     if (this.stage == 1) {
 159       const color = this.turn;
 160       // Post-processing: apply "checkerization" of standard moves
 161       const lastRank = (color == "w" ? 0 : 7);
 162       let moves = [];
 163       // King is treated differently: it never turn checkered
 164       if (this.getPiece(x, y) == V.KING) {
 165         // If at least one checkered piece, allow switching:
 166         if (
 167           this.canSwitch && !noswitch &&
 168           this.board.some(b => b.some(cell => cell[0] == 'c'))
 169         ) {
 170           const oppCol = V.GetOppCol(color);
 171           moves.push(
 172             new Move({
 173               start: { x: x, y: y },
 174               end: { x: this.kingPos[oppCol][0], y: this.kingPos[oppCol][1] },
 175               appear: [],
 176               vanish: []
 177             })
 178           );
 179         }
 180         return standardMoves.concat(moves);
 181       }
 182       standardMoves.forEach(m => {
 183         if (m.vanish[0].p == V.PAWN) {
 184           if (
 185             Math.abs(m.end.x - m.start.x) == 2 &&
 186             !this.pawnFlags[this.turn][m.start.y]
 187           ) {
 188             return; //skip forbidden 2-squares jumps
 189           }
 190           if (
 191             this.board[m.end.x][m.end.y] == V.EMPTY &&
 192             m.vanish.length == 2 &&
 193             this.getColor(m.start.x, m.start.y) == "c"
 194           ) {
 195             return; //checkered pawns cannot take en-passant
 196           }
 197         }
 198         if (m.vanish.length == 1)
 199           // No capture
 200           moves.push(m);
 201         else {
 202           // A capture occured (m.vanish.length == 2)
 203           m.appear[0].c = "c";
 204           moves.push(m);
 205           if (
 206             // Avoid promotions (already treated):
 207             m.appear[0].p != m.vanish[1].p &&
 208             (m.vanish[0].p != V.PAWN || m.end.x != lastRank)
 209           ) {
 210             // Add transformation into captured piece
 211             let m2 = JSON.parse(JSON.stringify(m));
 212             m2.appear[0].p = m.vanish[1].p;
 213             moves.push(m2);
 214           }
 215         }
 216       });
 217       return moves;
 218     }
 219     return standardMoves;
 220   }
 221
 222   getPotentialPawnMoves([x, y]) {
 223     const color = this.getColor(x, y);
 224     if (this.stage == 2) {
 225       const saveTurn = this.turn;
 226       if (this.sideCheckered == this.turn) {
 227         // Cannot change PawnSpecs.bidirectional, so cheat a little:
 228         this.turn = 'w';
 229         const wMoves = super.getPotentialPawnMoves([x, y]);
 230         this.turn = 'b';
 231         const bMoves = super.getPotentialPawnMoves([x, y]);
 232         this.turn = saveTurn;
 233         return wMoves.concat(bMoves);
 234       }
 235       // Playing with both colors:
 236       this.turn = color;
 237       const moves = super.getPotentialPawnMoves([x, y]);
 238       this.turn = saveTurn;
 239       return moves;
 240     }
 241     let moves = super.getPotentialPawnMoves([x, y]);
 242     // Post-process: set right color for checkered moves
 243     if (color == 'c') {
 244       moves.forEach(m => {
 245         m.appear[0].c = 'c'; //may be done twice if capture
 246         m.vanish[0].c = 'c';
 247       });
 248     }
 249     return moves;
 250   }
 251
 252   canIplay(side, [x, y]) {
 253     if (this.stage == 2) {
 254       const color = this.getColor(x, y);
 255       return (
 256         this.turn == this.sideCheckered
 257           ? color == 'c'
 258           : ['w', 'b'].includes(color)
 259       );
 260     }
 261     return side == this.turn && [side, "c"].includes(this.getColor(x, y));
 262   }
 263
 264   // Does m2 un-do m1 ? (to disallow undoing checkered moves)
 265   oppositeMoves(m1, m2) {
 266     return (
 267       !!m1 &&
 268       m2.appear[0].c == "c" &&
 269       m2.appear.length == 1 &&
 270       m2.vanish.length == 1 &&
 271       m1.start.x == m2.end.x &&
 272       m1.end.x == m2.start.x &&
 273       m1.start.y == m2.end.y &&
 274       m1.end.y == m2.start.y
 275     );
 276   }
 277
 278   filterValid(moves) {
 279     if (moves.length == 0) return [];
 280     const color = this.turn;
 281     const oppCol = V.GetOppCol(color);
 282     const L = this.cmoves.length; //at least 1: init from FEN
 283     const stage = this.stage; //may change if switch
 284     return moves.filter(m => {
 285       // Checkered cannot be under check (no king)
 286       if (stage == 2 && this.sideCheckered == color) return true;
 287       this.play(m);
 288       let res = true;
 289       if (stage == 1) {
 290         if (m.appear.length == 0 && m.vanish.length == 0) {
 291           // Special "switch" move: kings must not be attacked by checkered.
 292           // Not checking for oppositeMoves here: checkered are autonomous
 293           res = (
 294             !this.isAttacked(this.kingPos['w'], ['c']) &&
 295             !this.isAttacked(this.kingPos['b'], ['c']) &&
 296             this.getAllPotentialMoves().length > 0
 297           );
 298         }
 299         else res = !this.oppositeMoves(this.cmoves[L - 1], m);
 300       }
 301       if (res && m.appear.length > 0) res = !this.underCheck(color);
 302       // At stage 2, side with B & W can be undercheck with both kings:
 303       if (res && stage == 2) res = !this.underCheck(oppCol);
 304       this.undo(m);
 305       return res;
 306     });
 307   }
 308
 309   getAllPotentialMoves() {
 310     const color = this.turn;
 311     const oppCol = V.GetOppCol(color);
 312     let potentialMoves = [];
 313     for (let i = 0; i < V.size.x; i++) {
 314       for (let j = 0; j < V.size.y; j++) {
 315         const colIJ = this.getColor(i, j);
 316         if (
 317           this.board[i][j] != V.EMPTY &&
 318           (
 319             (this.stage == 1 && colIJ != oppCol) ||
 320             (this.stage == 2 &&
 321               (
 322                 (this.sideCheckered == color && colIJ == 'c') ||
 323                 (this.sideCheckered != color && ['w', 'b'].includes(colIJ))
 324               )
 325             )
 326           )
 327         ) {
 328           Array.prototype.push.apply(
 329             potentialMoves,
 330             this.getPotentialMovesFrom([i, j])
 331           );
 332         }
 333       }
 334     }
 335     return potentialMoves;
 336   }
 337
 338   atLeastOneMove() {
 339     const color = this.turn;
 340     const oppCol = V.GetOppCol(color);
 341     for (let i = 0; i < V.size.x; i++) {
 342       for (let j = 0; j < V.size.y; j++) {
 343         const colIJ = this.getColor(i, j);
 344         if (
 345           this.board[i][j] != V.EMPTY &&
 346           (
 347             (this.stage == 1 && colIJ != oppCol) ||
 348             (this.stage == 2 &&
 349               (
 350                 (this.sideCheckered == color && colIJ == 'c') ||
 351                 (this.sideCheckered != color && ['w', 'b'].includes(colIJ))
 352               )
 353             )
 354           )
 355         ) {
 356           const moves = this.getPotentialMovesFrom([i, j], "noswitch");
 357           if (moves.length > 0) {
 358             for (let k = 0; k < moves.length; k++)
 359               if (this.filterValid([moves[k]]).length > 0) return true;
 360           }
 361         }
 362       }
 363     }
 364     return false;
 365   }
 366
 367   // colors: array, 'w' and 'c' or 'b' and 'c' at stage 1,
 368   // just 'c' (or unused) at stage 2
 369   isAttacked(sq, colors) {
 370     if (!Array.isArray(colors)) colors = [colors];
 371     return (
 372       this.isAttackedByPawn(sq, colors) ||
 373       this.isAttackedByRook(sq, colors) ||
 374       this.isAttackedByKnight(sq, colors) ||
 375       this.isAttackedByBishop(sq, colors) ||
 376       this.isAttackedByQueen(sq, colors) ||
 377       this.isAttackedByKing(sq, colors)
 378     );
 379   }
 380
 381   isAttackedByPawn([x, y], colors) {
 382     for (let c of colors) {
 383       let shifts = [];
 384       if (this.stage == 1) {
 385         const color = (c == "c" ? this.turn : c);
 386         shifts = [color == "w" ? 1 : -1];
 387       }
 388       else {
 389         // Stage 2: checkered pawns are bidirectional
 390         if (c == 'c') shifts = [-1, 1];
 391         else shifts = [c == "w" ? 1 : -1];
 392       }
 393       for (let pawnShift of shifts) {
 394         if (x + pawnShift >= 0 && x + pawnShift < 8) {
 395           for (let i of [-1, 1]) {
 396             if (
 397               y + i >= 0 &&
 398               y + i < 8 &&
 399               this.getPiece(x + pawnShift, y + i) == V.PAWN &&
 400               this.getColor(x + pawnShift, y + i) == c
 401             ) {
 402               return true;
 403             }
 404           }
 405         }
 406       }
 407     }
 408     return false;
 409   }
 410
 411   isAttackedBySlideNJump([x, y], colors, piece, steps, oneStep) {
 412     for (let step of steps) {
 413       let rx = x + step[0],
 414           ry = y + step[1];
 415       while (V.OnBoard(rx, ry) && this.board[rx][ry] == V.EMPTY && !oneStep) {
 416         rx += step[0];
 417         ry += step[1];
 418       }
 419       if (
 420         V.OnBoard(rx, ry) &&
 421         this.getPiece(rx, ry) === piece &&
 422         colors.includes(this.getColor(rx, ry))
 423       ) {
 424         return true;
 425       }
 426     }
 427     return false;
 428   }
 429
 430   isAttackedByRook(sq, colors) {
 431     return this.isAttackedBySlideNJump(sq, colors, V.ROOK, V.steps[V.ROOK]);
 432   }
 433
 434   isAttackedByKnight(sq, colors) {
 435     return this.isAttackedBySlideNJump(
 436       sq, colors, V.KNIGHT, V.steps[V.KNIGHT], "oneStep");
 437   }
 438
 439   isAttackedByBishop(sq, colors) {
 440     return this.isAttackedBySlideNJump(
 441       sq, colors, V.BISHOP, V.steps[V.BISHOP]);
 442   }
 443
 444   isAttackedByQueen(sq, colors) {
 445     return this.isAttackedBySlideNJump(
 446       sq, colors, V.QUEEN, V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
 447   }
 448
 449   isAttackedByKing(sq, colors) {
 450     return this.isAttackedBySlideNJump(
 451       sq, colors, V.KING,
 452       V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep"
 453     );
 454   }
 455
 456   underCheck(color) {
 457     if (this.stage == 1)
 458       return this.isAttacked(this.kingPos[color], [V.GetOppCol(color), "c"]);
 459     if (color == this.sideCheckered) return false;
 460     return (
 461       this.isAttacked(this.kingPos['w'], ["c"]) ||
 462       this.isAttacked(this.kingPos['b'], ["c"])
 463     );
 464   }
 465
 466   getCheckSquares() {
 467     const color = this.turn;
 468     if (this.stage == 1) {
 469       // Artifically change turn, for checkered pawns
 470       this.turn = V.GetOppCol(color);
 471       const kingAttacked =
 472         this.isAttacked(
 473           this.kingPos[color],
 474           [V.GetOppCol(color), "c"]
 475         );
 476       let res = kingAttacked
 477         ? [JSON.parse(JSON.stringify(this.kingPos[color]))]
 478         : [];
 479       this.turn = color;
 480       return res;
 481     }
 482     if (this.sideCheckered == color) return [];
 483     let res = [];
 484     for (let c of ['w', 'b']) {
 485       if (this.isAttacked(this.kingPos[c], ['c']))
 486         res.push(JSON.parse(JSON.stringify(this.kingPos[c])));
 487     }
 488     return res;
 489   }
 490
 491   play(move) {
 492     move.flags = JSON.stringify(this.aggregateFlags());
 493     this.epSquares.push(this.getEpSquare(move));
 494     V.PlayOnBoard(this.board, move);
 495     if (move.appear.length > 0 || move.vanish.length > 0)
 496     {
 497       this.turn = V.GetOppCol(this.turn);
 498       this.movesCount++;
 499     }
 500     this.postPlay(move);
 501   }
 502
 503   postPlay(move) {
 504     if (move.appear.length == 0 && move.vanish.length == 0) {
 505       this.stage = 2;
 506       this.sideCheckered = this.turn;
 507     }
 508     else {
 509       const c = move.vanish[0].c;
 510       const piece = move.vanish[0].p;
 511       if (piece == V.KING) {
 512         this.kingPos[c][0] = move.appear[0].x;
 513         this.kingPos[c][1] = move.appear[0].y;
 514       }
 515       super.updateCastleFlags(move, piece);
 516       if (
 517         [1, 6].includes(move.start.x) &&
 518         move.vanish[0].p == V.PAWN &&
 519         Math.abs(move.end.x - move.start.x) == 2
 520       ) {
 521         // This move turns off a 2-squares pawn flag
 522         this.pawnFlags[move.start.x == 6 ? "w" : "b"][move.start.y] = false;
 523       }
 524     }
 525     this.cmoves.push(this.getCmove(move));
 526   }
 527
 528   undo(move) {
 529     this.epSquares.pop();
 530     this.disaggregateFlags(JSON.parse(move.flags));
 531     V.UndoOnBoard(this.board, move);
 532     if (move.appear.length > 0 || move.vanish.length > 0)
 533     {
 534       this.turn = V.GetOppCol(this.turn);
 535       this.movesCount--;
 536     }
 537     this.postUndo(move);
 538   }
 539
 540   postUndo(move) {
 541     if (move.appear.length == 0 && move.vanish.length == 0) this.stage = 1;
 542     else super.postUndo(move);
 543     this.cmoves.pop();
 544   }
 545
 546   getCurrentScore() {
 547     const color = this.turn;
 548     if (this.stage == 1) {
 549       if (this.atLeastOneMove()) return "*";
 550       // Artifically change turn, for checkered pawns
 551       this.turn = V.GetOppCol(this.turn);
 552       const res =
 553         this.isAttacked(this.kingPos[color], [V.GetOppCol(color), "c"])
 554           ? color == "w"
 555             ? "0-1"
 556             : "1-0"
 557           : "1/2";
 558       this.turn = V.GetOppCol(this.turn);
 559       return res;
 560     }
 561     // Stage == 2:
 562     if (this.sideCheckered == this.turn) {
 563       // Check if remaining checkered pieces: if none, I lost
 564       if (this.board.some(b => b.some(cell => cell[0] == 'c'))) {
 565         if (!this.atLeastOneMove()) return "1/2";
 566         return "*";
 567       }
 568       return color == 'w' ? "0-1" : "1-0";
 569     }
 570     if (this.atLeastOneMove()) return "*";
 571     let res = this.isAttacked(this.kingPos['w'], ["c"]);
 572     if (!res) res = this.isAttacked(this.kingPos['b'], ["c"]);
 573     if (res) return color == 'w' ? "0-1" : "1-0";
 574     return "1/2";
 575   }
 576
 577   evalPosition() {
 578     let evaluation = 0;
 579     // Just count material for now, considering checkered neutral at stage 1.
 580     const baseSign = (this.turn == 'w' ? 1 : -1);
 581     for (let i = 0; i < V.size.x; i++) {
 582       for (let j = 0; j < V.size.y; j++) {
 583         if (this.board[i][j] != V.EMPTY) {
 584           const sqColor = this.getColor(i, j);
 585           if (this.stage == 1) {
 586             if (["w", "b"].includes(sqColor)) {
 587               const sign = sqColor == "w" ? 1 : -1;
 588               evaluation += sign * V.VALUES[this.getPiece(i, j)];
 589             }
 590           }
 591           else {
 592             const sign =
 593               this.sideCheckered == this.turn
 594                 ? (sqColor == 'c' ? 1 : -1) * baseSign
 595                 : (sqColor == 'c' ? -1 : 1) * baseSign;
 596             evaluation += sign * V.VALUES[this.getPiece(i, j)];
 597           }
 598         }
 599       }
 600     }
 601     return evaluation;
 602   }
 603
 604   static GenRandInitFen(options) {
 605     const baseFen = ChessRules.GenRandInitFen(options.randomness);
 606     return (
 607       // Add 16 pawns flags + empty cmove + stage == 1:
 608       baseFen.slice(0, -2) + "1111111111111111 - - 1" +
 609       (!options["switch"] ? '-' : "")
 610     );
 611   }
 612
 613   static ParseFen(fen) {
 614     const fenParts = fen.split(" ");
 615     return Object.assign(
 616       ChessRules.ParseFen(fen),
 617       {
 618         cmove: fenParts[5],
 619         stage: fenParts[6]
 620       }
 621     );
 622   }
 623
 624   getCmoveFen() {
 625     const L = this.cmoves.length;
 626     return (
 627       !this.cmoves[L - 1]
 628         ? "-"
 629         : ChessRules.CoordsToSquare(this.cmoves[L - 1].start) +
 630           ChessRules.CoordsToSquare(this.cmoves[L - 1].end)
 631     );
 632   }
 633
 634   getStageFen() {
 635     if (this.stage == 1) return "1" + (!this.canSwitch ? '-' : "");
 636     // Stage == 2:
 637     return "2" + this.sideCheckered;
 638   }
 639
 640   getFen() {
 641     return (
 642       super.getFen() + " " + this.getCmoveFen() + " " + this.getStageFen()
 643     );
 644   }
 645
 646   getFenForRepeat() {
 647     return (
 648       super.getFenForRepeat() + "_" +
 649       this.getCmoveFen() + "_" + this.getStageFen()
 650     );
 651   }
 652
 653   getFlagsFen() {
 654     let fen = super.getFlagsFen();
 655     // Add pawns flags
 656     for (let c of ["w", "b"])
 657       for (let i = 0; i < 8; i++) fen += (this.pawnFlags[c][i] ? "1" : "0");
 658     return fen;
 659   }
 660
 661   static get SEARCH_DEPTH() {
 662     return 2;
 663   }
 664
 665   getComputerMove() {
 666     // To simplify, prevent the bot from switching (TODO...)
 667     return (
 668       super.getComputerMove(
 669         this.getAllValidMoves().filter(m => m.appear.length > 0)
 670       )
 671     );
 672   }
 673
 674   getNotation(move) {
 675     if (move.appear.length == 0 && move.vanish.length == 0) return "S";
 676     if (move.appear.length == 2) {
 677       // Castle
 678       if (move.end.y < move.start.y) return "0-0-0";
 679       return "0-0";
 680     }
 681
 682     const finalSquare = V.CoordsToSquare(move.end);
 683     const piece = this.getPiece(move.start.x, move.start.y);
 684     let notation = "";
 685     if (piece == V.PAWN) {
 686       if (move.vanish.length > 1) {
 687         const startColumn = V.CoordToColumn(move.start.y);
 688         notation = startColumn + "x" + finalSquare;
 689       } else notation = finalSquare;
 690     } else {
 691       // Piece movement
 692       notation =
 693         piece.toUpperCase() +
 694         (move.vanish.length > 1 ? "x" : "") +
 695         finalSquare;
 696     }
 697     if (move.appear[0].p != move.vanish[0].p)
 698       notation += "=" + move.appear[0].p.toUpperCase();
 699     return notation;
 700   }
 701
 702 };