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module ROOT =
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struct
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module Nat =
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struct
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type nat = Zero_nat | Suc of nat;;
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end;; (*struct Nat*)
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module Codegen =
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struct
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type 'a null = {null : 'a};;
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let null _A = _A.null;;
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let rec head _B = function x :: xs -> x
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| [] -> null _B;;
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let rec null_option = None;;
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let null_optiona () = ({null = null_option} : ('b option) null);;
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let rec dummy
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= head (null_optiona ()) [Some (Nat.Suc Nat.Zero_nat); None];;
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end;; (*struct Codegen*)
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end;; (*struct ROOT*)
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