Subject: Re: [boost] Heads up - string_ref landing
From: Dave Abrahams (dave_at_[hidden])
Date: 2012-12-15 17:48:18
on Wed Dec 12 2012, Gottlob Frege <gottlobfrege-AT-gmail.com> wrote:
> On Wed, Dec 12, 2012 at 10:49 AM, Rob Stewart <robertstewart_at_[hidden]>wrote:
>> >>> std::string does not have a 'null' state.
>> >> It's the state represented by empty().
>> > I am not sure it is so certainly accepted by all.
>> It is the logical interpretation. It indicates whether the string is
>> non-empty. I don't see any other generally useful interpretation, do you?
> Qt's QString has both empty() and isNull() and they are not always the
> same. Basically empty() is a zero-byte string, but null is a
> never-been-set-or-allocated string.
That's dumb, though.
> QString name = database.get("Name");
> name.empty() == true means the Name field was empty
> name.isNull() == true means the Name field doesn't exist in the database.
> Somewhat like optional<string>.
> I am NOT saying whether this is a good thing. Just a widely known example
> of interpretation.
I AM saying it's a bad thing! :-)
-- Dave Abrahams BoostPro Computing Software Development Training http://www.boostpro.com Clang/LLVM/EDG Compilers C++ Boost