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Date: Tue, 08 Dec 2009 11:06:54 +0100
From: Georg Bauhaus <rm.dash-bauhaus@futureapps.de>
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Subject: Re: Operation can be dispatching in only one type
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Date: 2009-12-08T11:06:55+01:00
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Dmitry A. Kazakov schrieb:
> In my view pre-/postconditions and
> invariants should be static, used strictly for program correctness proofs.
> Subtypes should complement them for dynamic run-time checks (recoverable
> faults).
> 

Hm. What would be your subtype based expression for

  generic
     type E is private;
  package Stacks  is


    type Stack is private;

    procedure push (Modified_Stack : in out Stack;
                    Another : Element)
         with pre => not Full (Modified_Stack),
              post => Size (Modified_Stack'Exit) = Size (Modified_Stack);

    procedure pop (Modified_Stack : in out Stack)
         with pre => not Empty (Modified_Stack),
              post => Empty (Modified_Stack);