Data.Natural

Support for natural numbers.

Documentation

data Natural

The type of natural numbers.

Note that matching a natural number against a negative pattern might not work as you expect. For example, evaluating the following expression results in a run-time error, instead of the result "plus five":

case 5 :: Natural of
    -5 -> "minus five"
     5 -> "plus five"

The reason is that the == operator of Natural is used for checking if the patterns match, making it necessary to convert -5 to Natural.

Instances

Enum Natural

Eq Natural

Integral Natural

Num Natural

Ord Natural

Read Natural

Real Natural

Show Natural

monus :: Natural -> Natural -> Natural

Yields the monus of two natural numbers, which is their difference if the first number is greater than the second, and zero otherwise.

data View

A data type for views of natural numbers.

Constructors

Zero

Succ Natural

view :: Natural -> View

Yields the view of a natural number.

fold :: accu -> (accu -> accu) -> Natural -> accu

Folding of natural numbers.