Why is there no 'math.round'?

[Asko Kauppi <askok@...>]

A rounding function would be a welcome addition to Lua's builtin  
'math.*' framework.

	math.round( x, 1 )		-- rounds to nearest integer
	math.round( x, 10 )	-- rounds to nearest 10*N

Is there any particular reason why Lua lacks one?

I did find this: http://lua-users.org/wiki/SimpleRound . However,  
ability to round to -say- 22.5 degrees or 500 meters would be useful.  
I.e. giving the rounding as number, not as exponent. Rounding mode  
could be an optional third parameters (nearest/towards zero/out of  
zero/...).

	--
	-- num= round( num [,step_num=1] )
	--
	-- Round 'num' to nearest N*'step' (step can be any positive number,  
i.e. 22.5)
	--
	local function round( v, step )
	    step= step or 1
	    assert( step > 0 )
	    return math.floor( (v+step/2) / step ) * step
	end

I didn't use this yet, may have a bug.


-asko