Data.Digit.Natural

Documentation

_NaturalDigits :: Prism' (NonEmpty DecDigit) Natural

>>> _NaturalDigits # 0
DecDigit0 :| []

>>> _NaturalDigits # 1
DecDigit1 :| []

>>> _NaturalDigits # 922
DecDigit9 :| [DecDigit2,DecDigit2]

>>> (DecDigit9 :| [DecDigit2,DecDigit2]) ^? _NaturalDigits
Just 922

>>> (DecDigit1 :| []) ^? _NaturalDigits
Just 1

\x -> digitsToNatural ( naturalToDigits x ) == Just x

naturalToDigits :: Natural -> NonEmpty DecDigit

>>> naturalDigits 0
DecDigit0 :| []

>>> naturalDigits 9
DecDigit9 :| []

>>> naturalDigits 393
DecDigit3 :| [DecDigit9,DecDigit3]

digitsToNatural :: NonEmpty DecDigit -> Maybe Natural

Create a number from a list of digits with the integer bounds of the machine.

>>> digitsToNatural (DecDigit3 :| [DecDigit4])
Just 34

>>> digitsToNatural (DecDigit0 :| [])
Just 0

>>> digitsToNatural (naturalToDigits (maxBound :: Natural))
Just 9223372036854775807

>>> digitsToNatural (naturalToDigits $ (maxBound :: Natural) + 1)
Nothing