Mate in one ♔

Chess library entirely written in Scala.

Usage ♕

The library is really easy to use. Just bring the mateinone package into scope.

import mateinone._

Alternatively, use sbt console and skip the imports as it is configured to pre-import everything.

The Board

Create a board in the initial position:

println(Board.initial)

The toString method outputs the following:

Board(Side(White,Map(h2 -> Pawn, f1 -> Bishop, a1 -> Rook, f2 -> Pawn, e1 -> King, d2 -> Pawn, g2 -> Pawn, e2 -> Pawn, c1 -> Bishop, d1 -> Queen, b2 -> Pawn, a2 -> Pawn, c2 -> Pawn, g1 -> Knight, b1 -> Knight, h1 -> Rook),Map(Knight -> Set(b1, g1), King -> Set(e1), Bishop -> Set(c1, f1), Queen -> Set(d1), Rook -> Set(a1, h1), Pawn -> Set(h2, f2, d2, g2, e2, b2, a2, c2)),Set()),Side(Black,Map(h7 -> Pawn, g8 -> Knight, h8 -> Rook, e8 -> King, g7 -> Pawn, a8 -> Rook, b7 -> Pawn, d7 -> Pawn, e7 -> Pawn, c7 -> Pawn, f8 -> Bishop, c8 -> Bishop, d8 -> Queen, b8 -> Knight, f7 -> Pawn, a7 -> Pawn),Map(Knight -> Set(b8, g8), King -> Set(e8), Bishop -> Set(c8, f8), Queen -> Set(d8), Rook -> Set(a8, h8), Pawn -> Set(h7, g7, b7, d7, e7, c7, f7, a7)),Set()),None,Vector(),0)

Pretty Print

Print a nicer presentation of the board using the print implicit method of TerminalPrinter.

import TerminalPrinter._

println(Board.initial.print)

Outputs the following:

┌─────────────────┐
│ ♜ ♞ ♝ ♛ ♚ ♝ ♞ ♜ │
│ ♟ ♟ ♟ ♟ ♟ ♟ ♟ ♟ │
│                 │
│                 │
│                 │
│                 │
│ ♙ ♙ ♙ ♙ ♙ ♙ ♙ ♙ │
│ ♖ ♘ ♗ ♕ ♔ ♗ ♘ ♖ │
└─────────────────┘

Make Moves

More things must be brought into scope so that squares and moves can be expressed.

import Square._
import MoveImplicits._

Play a simple trap known as the Scholar's mate:

1. e4 e5
2. Qh5 Nc6
3. Bc4 Nf6
4. Qxf7# 1–0

println(Board.initial.move(E2->E4, E7->E5, D1->H5, B8->C6, F1->C4, G8->F6, H5->F7).get.print)

┌─────────────────┐
│ ♜   ♝ ♛ ♚ ♝   ♜ │
│ ♟ ♟ ♟ ♟   ♕ ♟ ♟ │
│     ♞     ♞     │
│         ♟       │
│     ♗   ♙       │
│                 │
│ ♙ ♙ ♙ ♙   ♙ ♙ ♙ │
│ ♖ ♘ ♗   ♔   ♘ ♖ │
└─────────────────┘

Both sides play to quickly castle kingside:

1. Nf3 Nf6
2. g3 g6
3. Bh3 Bh6
4. O-O O-O

println(Board.initial.move(G1->F3, G8->F6, G2->G3, G7->G6, F1->H3, F8->H6, `O-O`, `O-O`).get.print)

┌─────────────────┐
│ ♜ ♞ ♝ ♛   ♜ ♚   │
│ ♟ ♟ ♟ ♟ ♟ ♟   ♟ │
│           ♞ ♟ ♝ │
│                 │
│                 │
│           ♘ ♙ ♗ │
│ ♙ ♙ ♙ ♙ ♙ ♙   ♙ │
│ ♖ ♘ ♗ ♕   ♖ ♔   │
└─────────────────┘

Make some exchanges:

1. d4 e5
2. dxe5 d6
3. Bg5 dxe5
4. Bxd8

println(Board.initial.move(D2->D4, E7->E5, D4->E5, D7->D6, C1->G5, D6->E5, G5->D8).get.print)

┌─────────────────┐
│ ♜ ♞ ♝ ♗ ♚ ♝ ♞ ♜ │
│ ♟ ♟ ♟     ♟ ♟ ♟ │
│                 │
│         ♟       │
│                 │
│                 │
│ ♙ ♙ ♙   ♙ ♙ ♙ ♙ │
│ ♖ ♘   ♕ ♔ ♗ ♘ ♖ │
└─────────────────┘

Generate Moves

Generate the opening moves and print them using the the toString method of Move:

println(Board.initial.moves)

Outputs the following:

Vector(b1->c3, b1->a3, g1->h3, g1->f3, h2->h4, f2->f4, d2->d4, g2->g4, e2->e4, b2->b4, a2->a4, c2->c4, h2->h3, f2->f3, d2->d3, g2->g3, e2->e3, b2->b3, a2->a3, c2->c3)

Scripts ♖

The script directory contains all the code above in basic.scala

The computer-computer-game.scala script plays both sides until the game is won or drawn.