Re: iterators

[Jim Pryor <lists+lua@...>]

On Tue, Nov 17, 2009 at 08:23:24AM -0500, Jim Pryor wrote:
> If you only have one
> loop---it doesn't matter how many iteration steps it involves---then
> only one object is getting created and so the garbage collection costs
> will be negligible. You're basically just testing here how much it slows
> down a function to lookup its upvalues. And the answer is, hardly any
> slowdown.

Sorry, I looked at your code again. I was wrong. You're not just running through a
single loop for each case, you are correctly creating the loop multiple
times.

However, your testing code doesn't do anything to manage when the
garbage collection costs are incurred. So for that reason you can't rely
on it for insight into the performance costs at issue here.

It would be better to insert a 
    collectgarbage("collect")
before the
    print(os.time()-t0)
in each block.

-- 
Jim Pryor
jim@jimpryor.net