Pull `bigint.lua` from `bigint.lua` repo

libs/bigint/bigint.lua

@@ -2,11 +2,12 @@
 -- If this variable is true, then strict type checking is performed for all
 -- operations. This may result in slower code, but it will allow you to catch
 -- errors and bugs earlier.
-local strict = false
+local strict = true
 
 --------------------------------------------------------------------------------
 
 local bigint = {}
+setmetatable(bigint, {__call = function(_, arg) return bigint.new(arg) end})
 
 local mt = {
     __add = function(lhs, rhs)
@@ -76,7 +77,7 @@ function bigint.new(num)
         end
     end
 
-    return self
+    return bigint.strip(self)
 end
 
 -- Check the type of a big
@@ -96,6 +97,14 @@ function bigint.check(big, force)
     return true
 end
 
+-- Strip leading zeroes from a big, but don't remove the last zero
+function bigint.strip(big)
+	while (#big.digits > 1) and (big.digits[1] == 0) do
+        table.remove(big.digits, 1)
+    end
+	return big
+end
+
 -- Return a new big with the same digits but with a positive sign (absolute
 -- value)
 function bigint.abs(big)
@@ -329,12 +338,7 @@ function bigint.subtract_raw(big1, big2)
     ----------------------------------------------------------------------------
 
 
-    -- Strip leading zeroes if any, but not if 0 is the only digit
-    while (#result.digits > 1) and (result.digits[1] == 0) do
-        table.remove(result.digits, 1)
-    end
-
-    return result
+    return bigint.strip(result)
 end
 
 -- FRONTEND: Addition and subtraction operations, accounting for signs
@@ -460,7 +464,7 @@ end
 function bigint.exponentiate(big, power)
     -- Type checking for big done by bigint.multiply
     assert(bigint.compare(power, bigint.new(0), ">="),
-           " negative powers are not supported")
+           "negative powers are not supported")
     local exp = power:clone()
 
     if (bigint.compare(exp, bigint.new(0), "==")) then
@@ -530,12 +534,7 @@ function bigint.divide_raw(big1, big2)
             end
         end
 
-        -- Remove leading zeros from result
-        while (result.digits[1] == 0) do
-            table.remove(result.digits, 1)
-        end
-
-        return result, dividend
+        return bigint.strip(result), dividend
     end
 end