Battler

A language for card games

Battler is an interpreter and card-game engine, an example of a Snap game can be seen below.

• PlainText to AST parser
• AST to bytecode compiler
• Bytecode interpreter can run test game file
• Interpreter runnable from command line
• Full Bytecode interpreter implementation
• Library published
• Python Plugin

Building this project

Use this project's simple CMakeLists.txt to build it, although it doesn't link with anything except for the C++ standard lib

Running a script

Run the interpreter against a game file: .\Battler.exe game_file.txt

Eve Online Snap Example Game

# this game is an implementation of Snap, but with ships
# from Eve Online

# it's a lot bigger than it has to be

game TestGame start

    visiblestack InPlay
    
    # a hidden stack
    hiddenstack Draw

    # number of players
    

    # stacks can have member attributes
    int Draw.x

    # member attributes can even be other stacks!
    privatestack Draw.h

    # and they can have attributes too!
    int Draw.h.y
    int Draw.h.a
    int Draw.h.b
    
    players 2

    Draw.h.b = 6

    int someVarName
    someVarName = 5*5
    
    # cards!
    card Ship start
        # card attributes
        int shield
        int armour
        int hull
        int attack
    end

    # child cards
    card Atron Ship start
        shield = 300 + 1
        armour = 350 * 2 - 1
        hull = 400 + 2 * 3
        attack = 50 + 60 * 6 - 5 / 4
    end
    
    # you dont have to set the attributes
    card Kestral Ship start end
    card Rifter Ship start end
    card Apocolypse Ship start end
    card Comet Ship start end

    # move random cards into a stack
    random Ship -> Draw top 100

    # move cards between stacks
    Draw -> InPlay top 2


    # a setup block, run once at the beggining of the game
    setup start
        foreachplayer p start
            privatestack p.Hand
            
            random Ship -> Draw top 10
            Draw ->_ p.Hand bottom 3
        end
    end

    # a phase declaration, like a function
    phase DrawPhase start
        Draw -> currentPlayer.Hand top 1
    end

    phase Place start
        currentPlayer.Hand -> InPlay top 1

        # compare cards from positions in stacks
        if InPlay.top == InPlay.top-1 start
            # declare a wiener
            winneris currentPlayer
        end
    end

    # runs every turn
    turn start
        # run a phase
        do DrawPhase
        do Place
    end
end

If you run the above game in the interpreter, you will get something like this output, showing it executing each turn automatically until ther is a winner

Compiling game file
Loading Compiled Game
Running game setup
The winner is 0