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Sender: "Team Ada: Ada Programming Language Advocacy (83 & 95)" <[log in to unmask]>
Date: Mon, 6 Jun 2005 10:12:10 +0200
Reply-To: Jean-Pierre Rosen <[log in to unmask]>
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From: Jean-Pierre Rosen <[log in to unmask]>
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Chris Sparks a écrit :
> The problem is that I rarely use discriminants.  It just seems silly to 
> me that given that there are initializers on the type definition below, 
> the compiler can deduce what the other value is for MR2 and MR3.  Now if 
> I didn't have initializers then that be a whole different matter.
Default value in discriminants are not really "default values" in the 
usual sense. Actually, it all happens the other way round. Let me explain:

1) A discriminant must be initialized.
2) But it is (sometimes) necessary to declare unconstrained variables
3) => Unconstrained variables are allowed only if all discriminants have 
default values.

In a sense, discriminant default values give the values of discriminants 
for *unconstrained variables*. They are not used in the declaration of 
*constrained* variables.

            J-P. Rosen ([log in to unmask])
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