peano - Lazy unary natural numbers
==================================
This package provides natural numbers in unary notation
```haskell
data Peano
= Zero
| Succ Peano
```
implementing `Num`, `Ord` etc.
Purpose
-------
One application is to check whether the length of a (potentially long) list is greater than a (small) number.
E.g., without optimization (`-O 0`),
```haskell
genericLength (replicate (10 ^ 6) True) >= (5 :: Peano)
```
outperforms the same test for `5 :: Int` by a factor of 10⁵, see [benchmark](bench/Main.hs):
```
length
Peano: OK
450 ns ± 45 ns
Int: OK
136 ms ± 4.1 ms
```