number.lua cleanup, tostring fixes

number.lua

@@ -1,50 +1,51 @@
 -- Make random random
 math.randomseed(minetest.get_us_time())
-for i = 1, 100 do
-    math.random()
-end
--- Number helpers
-function round(number, steps) -- Rounds a number
-    steps = steps or 1
-    return math.floor(number * steps + 0.5) / steps
+for _ = 1, 100 do math.random() end
+
+function round(number, steps)
+	steps = steps or 1
+	return math.floor(number * steps + 0.5) / steps
 end
+
 local c0 = ("0"):byte()
 local cA = ("A"):byte()
+
 function default_digit_function(digit)
-    if digit <= 9 then
-        return string.char(c0+digit)
-    end
-    return string.char(cA+digit-10)
+	if digit <= 9 then return string.char(c0 + digit) end
+	return string.char(cA + digit - 10)
 end
+
 default_precision = 10
+
+-- See https://github.com/appgurueu/Luon/blob/master/index.js#L724
 function tostring(number, base, digit_function, precision)
-    digit_function = digit_function or default_digit_function
-    precision = precision or default_precision
-    local out = {}
-    if number < 0 then
-        table.insert(out, "-")
-        number = -number
-    end
-    local digit
-    while number >= base do
-        digit = math.floor(number % base)
-        table.insert(out, digit_function(digit))
-        number = number / base
-    end
-    digit = math.floor(number)
-    table.insert(out, digit_function(digit))
-    modlib.table.reverse(out)
-    number = number % 1
-    if number >= math.pow(base, precision) then
-        table.insert(out, ".")
-        -- precision >= 0 eventually redundant
-        while precision >= 0 and number >= math.pow(base, precision) do
-            number = number * base
-            digit = math.floor(number % base)
-            table.insert(out, digit_function(digit))
-            number = number - digit
-            precision = precision - 1
-        end
-    end
-    return table.concat(out)
+	digit_function = digit_function or default_digit_function
+	precision = precision or default_precision
+	local out = {}
+	if number < 0 then
+		table.insert(out, "-")
+		number = -number
+	end
+	number = number + base ^ -precision / 2
+	local digit
+	while number >= base do
+		digit = math.floor(number % base)
+		table.insert(out, digit_function(digit))
+		number = number / base
+	end
+	digit = math.floor(number)
+	table.insert(out, digit_function(digit))
+	modlib.table.reverse(out)
+	number = number % 1
+	if number ~= 0 and number >= base ^ -precision then
+		table.insert(out, ".")
+		while precision >= 0 and number >= math.pow(base, precision) do
+			number = number * base
+			digit = math.floor(number % base)
+			table.insert(out, digit_function(digit))
+			number = number - digit
+			precision = precision - 1
+		end
+	end
+	return table.concat(out)
 end