tail call recursion and faux threads by timeslicing

tcall.js

var tcallq = [];

function utime() {
  return Date.now();
}

function call2(f,t,a) {
  var r = f && function() {
    return f.apply(t,a);
  };
  return r;
}

function tcall(f,that,args) {

    var lastyield = utime(); 

    function recurse() {
      while(f) {
        f = f.apply(that,args) || tcallq.pop();
        var t = utime();
        if(f && t - lastyield > 50) {
          lastyield = t;
          setTimeout(recurse);
          break;
        }
      }
    }

    recurse();

}

/*
function lotsOfWork(count) {
  tcall(function chunk() {
    console.log(count);
    if(count--) return chunk;
  },this);
}
*/