[jira] Commented: (BOO-484) For loop similar to Basic's for <var> = <start> to <end> [step <step>]:

    [ http://jira.codehaus.org/browse/BOO-484?page=comments#action_46080 ] 

Daniel Grunwald commented on BOO-484:
-------------------------------------

Currently that optimization is not implemented.
                static void Test(int start, int max, int step)
                {
                        Console.WriteLine("before loop");
                        for (int i = start; i < max; i += step) {
                                Console.WriteLine(i);
                        }
                        Console.WriteLine("after loop");
                }
compiles to EXACTLY the same IL as
def Method(start as int, end as int, step as int):
        Console.WriteLine("before loop")
        i = start
        while i < end:
                Console.WriteLine(i)
                i += step
        Console.WriteLine("after loop")

So the "for i in range()" optimization can be done with simple pipeline step.

> For loop similar to Basic's for <var> = <start> to <end> [step <step>]:
> -----------------------------------------------------------------------
>
>          Key: BOO-484
>          URL: http://jira.codehaus.org/browse/BOO-484
>      Project: Boo
>         Type: New Feature
>  Environment: All
>     Reporter: Cameron Kenneth Knight
>     Priority: Minor

>
>
> Boo's current for loop with range is much slower than C#'s simpler for loop
> If we were to go with Basic's syntax of 
> for <var> = <start> to <end> [step <step>]:
>     <block>
> Which, would give the same result as
> for <var> in range(<start>, <end>[, <step>]):
>     <block>
> but could be made a lot faster.
> I ran a test where I, in C#, iterated through a for loop 1,000,000,000 times, 
> taking 1.75 seconds.
> I then ran a test in Boo that iterated through its for loop using range 
> 1,000,000,000 times, taking 47.58 seconds.
> I don't know if there is another way to make the for-range statement faster, 
> but the way I proposed can cut out the enumerator altogether.

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