function tco(g){
    //arguments
    g.__first = true;
    g.__cont = {};
    g.__original = g
    g.__tco = function (){
        var r;
        if(g.__first){
            g.__first = false;
            for(;;){
                var r = g.apply(this,arguments)
                if (g.__cont === r){
                    arguments = g.__args //update arguments
                } else {
                    g.__first = true;
                    return r;
                }
            }
        } else {
            g.__args = arguments;
            return g.__cont;
        }
    }
    return g.__tco
}

function f(n,sum){
    return (n>0)? f(n-1,sum+n) : sum;
}


function even(n){return n==0 ? true : odd(n-1)}
function odd(n){return n==0 ? false : even(n-1)}

f = tco(f)
console.log(f(1000000,0))
even = tco(even)
odd = tco(odd)
console.log(odd(10000000))