Re: [boost] Re: Re: Variant implementation change (was re: unions) finalsummary

From: E. Gladyshev (egladysh_at_[hidden])
Date: 2003-10-09 15:02:24

--- Rainer Deyke <rainerd_at_[hidden]> wrote:
> Brock Peabody wrote:
> > (5) If variant can be singular you will need an additional case for
> > each variant and possibly turn many compile-time errors into run-time
> > errors.
> > This is a fact too.
> 
> While trivially true, I doubt this is actually important in real code.  If a
> variant operation that only provides the basic guarantee throws, the state
> of the variant is "valid" but undefined.  This means that the variant
> contains no useful data, and the invariants of the piece of code which uses
> the variant may (temporarily) be broken.  The only meaningful responses to
> the exception are therefore to replace the value in the variant with another
> (potentially resulting in another exception) or to destroy the variant
> (explicitly or implictly).
> 

Agree, exactly my point.

Eugene

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