From: David Abrahams (dave_at_[hidden])
Date: 2003-02-18 13:29:39
"Ed Brey" <brey_at_[hidden]> writes:
> Extract is confusing. One problem is that it is deceivingly named.
The name was my suggestion, so I'm going to argue with you a bit about
> It doesn't extract data from the variant at all, but rather provides
> type-specific access to data that still resides in the variant.
"Provides type-specific access to data that still resides in the
variant" is a mouthful, but I'm still not sure what it means. How is
it different from extracting the data?
> It is not clear from the name or the documentation that this would
> be bad:
> variant<int>* v = new variant<int>; extract<int> i(*v); delete v;
> return i;
Ugh. Is it clear from the name that this would be bad?
std::back_insert_iterator<std::vector<int> > f()
If the documentation for extract doesn't say that behavior is
undefined if extraction occurs after the constructor argument is
destroyed, it should. Wouldn't that cover your (rather implausible)
> The area would be helped by renaming extract to access.
How is "access" any clearer? "Access" can plausibly be interpreted as
a noun or a verb in the context of variant, so I don't like it very
BTW, I just realized that a conversion from variant<T> to optional<T>
could be used to do extraction as well. Maybe it would be better to
ditch extract altogether and just use optional?
-- Dave Abrahams Boost Consulting www.boost-consulting.com
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