Question for Dave Herman.

istailcall.js

function foo(){
    var temp = bar();
    return temp;
}

/*
	Is this a tail call? the call to bar is not actually in tail position, however 
	it is the last instruction to 	execute before the return expression. Let me know. 
*/

No, it's not a tail call. When people explain tail calls as "the last thing a function does" they're explaining the intuition but being imprecise. Proper tail calls are really about describing a syntactic category of positions known as tail position, and guaranteeing that the implementation uses a bounded amount of space for calls in tail position. Since, as you say, the call to bar in this example is not in tail position, it is not a tail call.

Dave