Befunge code

befunge.js

var Befunge = function () {
    
    var WIDTH = 80,
        HEIGHT = 25,
        x = 0, 
        y = 0,
        output = [], // This is array for storing output
        stack = [],
        matrix;
    
    function _preAllocateArray (width, height) {
        
        var array = new Array(width);
        for (var i = 0; i < width; i++) {
            array[i] = new Array(height);
        }
        return array;
    }
    
    function init() {
        x = 0;
        y = 0;
        
        matrix = _preAllocateArray(WIDTH, HEIGHT);
        
    }
    
    function addition () {
        console.log("addition called");
        
        var a = stack.pop(),
            b = stack.pop(),
            result = a + b;
        stack.push(result);
        
        return result;
    }
    
    function subtraction () {
        var a = stack.pop(),
            b = stack.pop(),
            result = b - a;
        stack.push(result);
        
        return result;
    }

    function multiplication () {
        var a = stack.pop(),
            b = stack.pop(),
            result = a * b;
        stack.push(result);
        
        return result;
    }

    function division () {
        var a = stack.pop(),
            b = stack.pop(),
            result;
            
        if (a === 0) {
            result = 0;
        } else {
            result = Math.floor(b / a);
        }
        stack.push(result);
        
        return result;
    }
    
    function modulo () {
        var a = stack.pop(),
            b = stack.pop(),
            result;
            
        if (a === 0) {
            result = 0;
        } else {
            result = b % a;
        }
        stack.push(result);
        
        return result;      
    }
    
    function logicalNot () {
        var a = stack.pop();
        result = (a === 0) ? 1 : 0;
        stack.push(result);
        return result;
    }
    
    function greaterThan () {
        var a = stack.pop(),
            b = stack.pop(),
            result;
        result = (b > a) ? 1 : 0;
        stack.push(result);
        return result;
    }
    
    function moveRight () {
        console.log('Move right');
    }

    function moveLeft () {
        console.log('Move left');
    }
    
    function moveUp () {
        console.log('Move up');
    }
    
    function moveDown () {
        console.log('Move down');
    }
    
    function match (instruction) {
        var instructions = {
            '+': addition,
            '-': subtraction,
            '*': multiplication,
            '/': division,
            '%': modulo,
            '!': logicalNot,
            '`': greaterThan,
            '>': moveRight,
            '<': moveLeft,
            'v': moveDown,
            '^': moveUp
        }
        
        if (instruction in instructions) {
            // Call the instruction
            instructions[instruction]();
        } else if (parseInt(instruction, 10) !== NaN) {
            stack.push(parseInt(instruction, 10));
        } else {
            // Unknown instruction, push it to stack
            stack.push(instruction);
        }
    }
    
    function interpret (code) {
        var lines = code.split('\n'),
            instructions,
            instruction;
        
        init();
        
        for (var x = 0; x < lines.length; x++) 
        {
            instructions = lines[x].split('');
            
            for (var y = 0; y < instructions.length; y++) 
            {
                instruction = instructions[y];
                
                matrix[x][y] = instruction;
                match(instruction);
            }
            
        }
        _print();

        console.log('Stack', stack);
    }
    
    function _print() {
        var str = '';
        for (var x = 0; x < matrix.length; x++) {
            for (var y = 0; y < matrix[0].length; y++) {
                
                if (matrix[x][y] !== undefined) {
                    str += matrix[x][y];    
                } else {
                    str += '.';
                }
                
            }
            str += '\n';
        }
        console.log(str);
    }
    
    return {
        "interpret": interpret
    }
}();

Befunge.interpret("34+2*4-2/3%0!\n+@\n><");