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(*---------------------------------------------------------------------------
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* This structure is intended to shield TFL from any constructors already
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* declared in the environment. In the Isabelle port, for example, there
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* was already a datatype with "|->" being a constructor. In TFL we were
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* trying to define a function "|->", but it failed in PolyML (which conforms
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* better to the Standard) while the definition was accepted in NJ/SML
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* (which doesn't always conform so well to the standard).
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*---------------------------------------------------------------------------*)
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structure Mask : Mask_sig =
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struct
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datatype 'a binding = |-> of ('a * 'a) (* infix 7 |->; *)
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datatype mask = ERR
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end;
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