From: Fernando Cacciola (fernando_cacciola_at_[hidden])
Date: 2002-12-12 17:09:53
"William E. Kempf" <wekempf_at_[hidden]> wrote in message
> Fernando Cacciola said:
> > Due to some significant changes to the optional<> class, I had to upload
> > a new version so that the review can continue based on the revised
> > class.
> > http://groups.yahoo.com/group/boost/files/optional.zip
> > The new zip contains the new code, new test and new documentation.
> > NOTE: The header optional_detail is no longer needed so you may remove
> > it before unpacking the zip.
> Documentation issues/questions:
> * "its safe on most platforms which treat null pointer dereferencing as
> undefined behaviour which is effectively a core dump or an non-language
> I know what you're saying here, but I don't like it. Undefined behavior
> is undefined behavior, and can never be considered "safe". I'm not sure
> how to rework it to convey what you want, but I think it needs reworked.
OK. You're right. The wording is incorrect.
> * The "safe bool" should be documented in the same manner as it is in
> shared_ptr, i.e. "operator unspecified-bool-type() const; // never
I figure that if I can borrow the implementation I can borrow the
documentation too :-)
> * Does the "assert(*opt == v)" in the description for "explicit
> optional<T>::optional( T const& v )" indicate that the type T must be
> comparable? (I know the documentation clearly says otherwise, but it's
> not clear that this is a non-normative part of the documentation.)
That form of asserts are intended to show the postconditions that hold
after each of the operations described.
But they are not meant to imply that the type T must support the expression;
rather that if the expression is defined, then the condition must hold.
Pehaps a a note to this effect can be added before the semantics
> * In the acknowledgements for Gennadiy Rozental you describe the "value
> based" implementation which no longer exists.
Anyway, after the review I will have to add several entries to this section
> Interface issues/questions:
> * Is there a reason for operator!() when we have the safe bool?
I left it because shared_ptr has it.
I figure that there must be some contexts where the safe_bool conversion
> * Should you provide a templated assignment to parallel the templated
Another good question!
I can't see why not... if it is correct to have one it is correct to have
the other, IMO.
-- Fernando Cacciola
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