22 lines
536 B
Standard ML
22 lines
536 B
Standard ML
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structure System =
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struct
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structure Unsafe =
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struct
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structure Susp =
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struct
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type 'a susp = 'a Lazy.t
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fun delay f = (ref (Lazy.Delayed f) : 'a susp)
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fun force (f : 'a susp) = Lazy.force f
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end
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end
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end
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fun null x = x = []
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fun fold f = List.fold_right (fn x => fn y => f (x, y))
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fun foldl f = List.fold_left (fn x => fn y => f (y, x))
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fun foldr f = List.fold_left (fn x => fn y => f (y, x))
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val rev = List.rev
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val length = List.length
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val map = List.map
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