local function escape_pattern(s)
	return (s:gsub("(%W)", "%%%1"))
end

function Thousands(n, sep)
	sep = sep or "."
	local s = tostring(n)
	local sign, int, frac = s:match("^([%-]?)(%d+)(%.?%d*)$")

	int = int:reverse():gsub("(%d%d%d)", "%1" .. sep):reverse()

	local sep_esc = escape_pattern(sep)
	int = int:gsub("^" .. sep_esc, "")

	return sign .. int .. frac
end