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Or who needs non-strict semantics when you have references?
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let Y (Fs : (('a -> 'b) list -> 'a -> 'b) list) : ('a -> 'b) list = let refs = [ for _ in Fs -> ref Unchecked.defaultof<'a -> 'b> ] let etaExpanded = refs |> List.map (fun fp -> (fun x -> fp.Value x)) Fs |> List.map (fun F -> F etaExpanded) |> List.zip refs |> List.iter (fun (fp, f) -> fp := f) etaExpanded // example #nowarn "25" let [even; odd] = let even = fun [even; odd] n -> n = 0 || odd (n-1) let odd = fun [even; odd] n -> n <> 0 && even (n-1) Y [even; odd] odd 2013
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y combinator
polyvariadic fixpoint
y combinator
polyvariadic fixpoint
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