Created
March 24, 2017 03:16
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YCombinator.swift
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| func fix<T, U>(_ f: @escaping (@escaping (T) -> U) -> (T) -> U) -> (T) -> U | |
| { | |
| return { f(fix(f))($0) } | |
| } | |
| let fib: (Int) -> Int = fix { f in { n in if n < 2 { return 1 } else { return f(n - 1) + f(n - 2) } } } | |
| fib(1) | |
| fib(2) | |
| fib(3) | |
| fib(4) | |
| let factorial: (Int) -> Int = fix { f in { n in if n == 1 { return 1 } else { return n * f(n - 1) } }} | |
| factorial(1) | |
| factorial(2) | |
| factorial(3) |
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