This is a library for working with numbers of arbitrarily finite size.
Javascript (and to some extension Purescript) has quite a few drawbacks when it comes to large numbers. For example, Purescript's Int primitive is a member of the Bounded typeclass, with top == 2 ^ 31 - 1 and bottom == - (2 ^ 32).
The Purescript Number primitive is not Bounded in the same way; however, there are problems with manipulating large-enough Numbers:
> import Prelude
> let x = 900000000000000000.0
> :t x
Number
> x + 1.0 == x
true
> x + 1.0
900000000000000000
In this library, correctness is prioritized above all else:
> import Data.HugeNum
> let x = fromNumber 900000000000000000.0
> let y = fromNumber 1.0
> x + y == x
false
> x + y
HugeNum 900000000000000001.0
Addition is implemented using an elementary-school method. Multiplication follows Karatsuba.
Available on pursuit.
There is also a newtype for integral values in Data.HugeInt.
bower install purescript-hugenums