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From: eric@burdvax.UUCP
Newsgroups: comp.lang.ada
Subject: Re: Constrained Boolean
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Date: Fri, 17-Apr-87 20:46:17 EST
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Posted: Fri Apr 17 20:46:17 1987
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in article <880@aw.sei.cmu.edu.sei.cmu.edu>, (Robert Firth) says:
> 
> If somebody constrains a Boolean subtype
> to one value, then the following holds
> 
>   ...
>
>   . NOT and XOR will always raise CONSTRAINT_ERROR
> 

  The elaboration of 'a' below will not raise CONSTRAINT_ERROR.

  subtype bool is boolean range true..true;
  a : bool := true xor false;