A concurrent crossword game engine and robot, written in Go

GoSkrafl is a fast, concurrent crossword game engine and auto-playing robot. It is a package for the Go programming language, licensed under CC-BY-NC 4.0. It has been tested on Linux and Windows, and probably works fine on MacOS too.

Out of the box, GoSkrafl supports OTCWL2014, SOWPODS, OSPS37, Norwegian and Icelandic dictionaries and corresponding tile sets. But as it employs Unicode and UTF-8 throughout, GoSkrafl can easily be tweaked to accommodate most natural languages and dictionaries, and any tile bag configuration. (The only limitation is that there cannot be more different letters in an alphabet than there are bits in the native uint type.)

The GoSkrafl package encompasses the whole game lifecycle, board, rack and bag management, move validation, scoring, word and cross-word checks, as well as robot players.

The robot players make good use of Go's goroutines to discover valid moves concurrently, employing all available processor cores for parallel execution of multiple worker threads. This, coupled with Go's compilation to native machine code, and its efficient memory management, makes GoSkrafl quite fast. (As an order of magnitude, it runs at over 25 simulated OTCWL2014 games per second on a quad-core Intel i7-4400 processor @ 3.4 GHz, or less than 40 milliseconds per game.)

The design and code of GoSkrafl borrow heavily from a battle-hardened crossword game engine in Python by the same author.

GoSkrafl is well tested and in production. Issues and pull requests are welcome.

To add support for a new dictionary, assemble the word list in a UTF-8 text file, with all words in lower case, one word per line. Use the DAWG builder from Netskrafl to build a .bin.dawg file. Copy it to the /GoSkrafl/dicts/ directory, then add a snippet of code at the bottom of dawg.go to wrap it in an instance of the Dawg class. Remember to add an alphabet string as well, cf. the IcelandicAlphabet, EnglishAlphabet and PolishAlphabet variables. The same alphabet string must be used for the encoding in dawgbuilder.py. Post an issue if you need help.

To enjoy seeing two robots slug it out in a game:

package main

import (
    "fmt"
    skrafl "github.com/vthorsteinsson/GoSkrafl"
)

func main() {
    // Set up a game using the SOWPODS dictionary
    game := skrafl.NewSowpodsGame()
    game.SetPlayerNames("Robot A", "Robot B")
    // Create a robot that always selects
    // the highest-scoring valid move
    robot := skrafl.NewHighScoreRobot()
    // Print the initial game board and racks
    fmt.Printf("%v\n", game)
    // Generate moves until the game ends
    for {
        // Extract the game state
        state := game.State()
        // Find the highest-scoring move available
        move := robot.GenerateMove(state)
        // Apply the (implicitly validated) move to the game
        game.ApplyValid(move)
        // Print the new game state after the move
        fmt.Printf("%v\n", game)
        if game.IsOver() {
            fmt.Printf("Game over!\n")
            break
        }
    }
}

A fancier main program for exercising the GoSkrafl engine can be found here.

Vilhjálmur Þorsteinsson, Reykjavík, Iceland.

Contact me via GitHub for queries or information regarding GoSkrafl, for instance if you would like to use GoSkrafl as a basis for your own game program, server or website but prefer not to do so under the conditions of the CC-BY-NC 4.0 license (see below).

GoSkrafl - a concurrent crossword game engine and robot, written in Go

Copyright (C) 2024 Vilhjálmur Þorsteinsson / Miðeind ehf.

This set of programs is licensed under the Creative Commons Attribution-NonCommercial 4.0 International Public License (CC-BY-NC 4.0).

The full text of the license is available here: https://creativecommons.org/licenses/by-nc/4.0/ - as well as in the LICENSE file in this repository.

SCRABBLE is a registered trademark. This software or its author are in no way affiliated with or endorsed by the owners or licensees of the SCRABBLE trademark.