gistfile1.js

// my solution to exercise 5 of "you can't javascript under pressure"
// http://toys.usvsth3m.com/javascript-under-pressure/
function arraySum(i) {
    
    // i will be an array, containing integers, strings and/or arrays like itself.
    // Sum all the integers you find, anywhere in the nest of arrays.
    var sum = 0;
    var counter = 0;
    var stack = [];
    var call=false;
    var retval = null;
    stack.push({'counter':counter, 'i': i, 'sum': 0});
    
    while (stack.length > 0){
        // pop the current state off the stack
        var state = stack.pop();
        sum = state['sum'];
        counter=state['counter'];
        i=state['i'];
        
        // if we're returning from a function call..
        if (retval !== null){
            sum += retval;
            retval = null;
        }
        
        var idx = 0;
        while (counter < i.length){
            idx = counter++;
            if (typeof(i[idx]) =='number'){
                sum += i[idx];
            }
            else if (typeof(i[idx]) == 'object'){
                // push current state onto stack before jumping to function
                stack.push({'counter':counter, 'i': i, 'sum': sum});
                call=true;
                break;
            }
        }
        
        if (call){
            call=false;
            // push parameters of the function call onto the stack
            stack.push({'counter':0, 'i': i[idx], 'sum': 0})
        }
        else {
            retval = sum;
        }
    }
    
    return sum;
    
}