Module:Decimals

This Lua module is used on approximately 5,600 pages and changes may be widely noticed. Test changes in the module's /sandbox or /testcases subpages, or in your own module sandbox. Consider discussing changes on the talk page before implementing them.

This module is subject to page protection. It is a highly visible module in use by a very large number of pages, or is substituted very frequently. Because vandalism or mistakes would affect many pages, and even trivial editing might cause substantial load on the servers, it is protected from editing.

Usage[edit]

From other Lua modules[edit]

local roundAndPad = require('Module:Decimals')._main
result = roundAndPad(n, decimals)

From wikitext[edit]

{{#invoke:Decimals|main|n|decimals}}

For more information, see Template:Decimals.

require('Module:No globals')

local p = {}

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

function p.main(frame)
	local args, pargs = frame.args, frame:getParent().args
	local function work()
		return p._main(
			mw.ext.ParserFunctions.expr(args[1] or pargs[1]),
			mw.ext.ParserFunctions.expr(args[2] or pargs[2])
		)
	end
	local success, result = pcall(work)
	if success then
		return result
	end
	local errtext = args.error or pargs.error
	if errtext then
		return errtext
	end
	error(result, 0)
end

return p