DEPRECATED: Purescript v0.15.0 now provides typelevel integers with compiler solved typeclasses, so there is no need anymore to use symbol-based arithmetic.
Arithmetic at the typelevel using symbols.
add ∷
∀ augend addend sum carry result.
Add augend addend carry sum ⇒
Cons carry sum result ⇒
Proxy augend → Proxy addend → Proxy result
add _ _ = Proxy
result ∷ Proxy "0579"
result = add (term ∷ _ "123") (term ∷ _ "456")