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From: "Randy Brukardt" <randy@rrsoftware.com>
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Subject: Re: Discriminants or Constructor Function for Limited Types
Date: Mon, 9 May 2022 23:48:35 -0500
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"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:t57vgs$4su$1@gioia.aioe.org...
...
> No they do not. The goal is to eliminate non-functional states. Things 
> like closed file, uninitialized variable, null pointer etc are artifacts 
> of the design. There is nothing in the physical world that requires them.

Most such things are artifacts of the target system. Closed files and closed 
windows happen because of events that occur outside of your program. You 
can't design them away.

                             Randy.