Module:Decimals

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This module depends on the following other modules:

• Module:Arguments

The above documentation is transcluded from Module:Decimals/doc. (edit | history)
Editors can experiment in this module's sandbox (create | mirror) and testcases (create) pages.
Subpages of this module.

local p = {}
local getArgs

function p.main(frame)
	if not getArgs then
		getArgs = require('Module:Arguments').getArgs
	end
	local args = getArgs(frame, {
		wrappers = 'Template:Decimals'
	})
	return p._main(args[1], args[2])
end
function p._main(n, d)
	local num = tonumber(n)
	if not num then
		error('Unable to convert "' .. tostring(n) .. '" to a number')
	end
	local decimals = tonumber(d)
	if not decimals then
		error('Unable to convert "' .. tostring(d) .. '" to a number')
	end
	local maxDecimals = 14 - math.floor(math.log10(num)) -- to allow a maximum of 15 significant figures, which is the highest guaranteed correct with doubles
	if decimals > maxDecimals then decimals = maxDecimals end
	local mult = 10^decimals
	num = math.floor(num * mult + 0.5) / mult
	if decimals < 0 then
		return tostring(num)
	else
		return string.format('%.' .. decimals .. 'f', num)
	end
end

return p