On 6/9/11 12:06 PM, Ben Grabham wrote:
Also, how come recurrence isn't properly lazy? If I define a recurrence and iterate over it twice with foreach, it takes the same amount of time due to the stack size being set. Is there a way of defining a lazy list that stores the results when calculated?
recurrence() is very simple: it starts with the state you pass to it. Then each popFront() overwrites the head of the state (heh) with the calculated value from the existing state.
I agree that one could delay any computation until the initial state is exhausted - for example, if the state size is 100, then there's no need to do anything for the first 99 steps. That's far from a common case however as most recurrences have small states and are iterated numerous times. The necessary bookkeeping would slow down that common case a bit.
Andrei
