/**
 * Spaghetti's in built operators
 * @type {Object}
 */
let operators = {
    print(stack) {
        let numArgs = stack.pop();

        for (var i = 0; i < numArgs; i += 1) {
            console.log(stack.pop());
        }
        return {
            stack
        };
    }
};

// Arithmetic operators
Object.assign(operators, require("./operators/arithmetic"));

module.exports = operators;

@@ -272,16 +272,175 @@
 %7D;%0A    %7D
+,%0A    dup(stack) %7B%0A        let value = stack.pop();%0A%0A        stack.push(value);%0A        stack.push(value);%0A        return %7B%0A            stack%0A        %7D;%0A    %7D,
 %0A%7D;%0A%0A// 

Add stack value duplication