Re: Why is there no 'math.round'?

[askok@...]

I am in the position to help a customer transition to Lua, 
and I'm sure they'll ask question s.a. where's "round" 
when we start going specific.

And since I didn't have the reason for abandoning 'round' 
I wanted to ask. That's all.

The specific variant I'd like to have is

function round( v, step )
    return math.floor( v*step +0.5 ) / step
end

This is the kind of things that just should "be there" (as 
most is, already). Maybe I'll just inject a 'math.round' 
to them myself, to avoid sticking to this issue and 
focusing on the language itself, instead.

Mark Hamburg nailed the reasoning right:
> In adding a rounding function, there's a disincentive to add it to math itself because the Lua distribution conceptually controls that namespace. So one adds mymath.round. (Lightroom has AgMathUtils.round.) But then everyone goes off and re-invents this and when one wants to share code we run into problems.

The round above already causes a clash compared to the one 
on the Wiki (2nd param works differently).

-asko


On Wed, 23 Apr 2008 10:43:02 -0400
 "Mike Crowe" <drmikecrowe@gmail.com> wrote:
> What's the specific request that we are trying to 
> define?  math.round(value,
> precision) for non-integer rounding?
>
> I'm confused about what is being requested.  I agree 
> with the earlier
> observation that floor/ceil give us everything we need:
>
> > a = 12.345678
> > print(math.floor(a+0.5))
> 12
> > print(math.floor(a*10+0.5)/10)
> 12.3
> > print(math.floor(a*100+0.5)/100)
> 12.35
>
> Am I missing something very obscure?