Home
Insert
Update snippet 'Church numerals'
Title
Description
Church numerals via rank-2 polymorphism
Source code
type Church = abstract Apply<'T> : ('T -> 'T) * 'T -> 'T let zero = { new Church with member self.Apply(f, x) = x } let succ (nat : Church) = { new Church with member self.Apply(f, x) = f <| nat.Apply(f, x) } let one = succ zero let two = succ one let (<+>) (first : Church) (second : Church) = first.Apply(succ, second) let (<*>) (first : Church) (second : Church) = first.Apply((<+>) second, zero) let (<^>) (first : Church) (second : Church) = second.Apply((<*>) first, one) let toInt (nat : Church) = nat.Apply((+)1, 0) let three = two <+> one let six = three <*> two let eight = two <^> three three |> toInt // 3 six |> toInt // 6 eight |> toInt // 8
Tags
rank-2 polymorphism
church numerals
rank-2 polymorphism
church numerals
Author
Link
Reference NuGet packages
If your snippet has external dependencies, enter the names of NuGet packages to reference, separated by a comma (
#r
directives are not required).
Update
