RE: [boost] Re: safe_bool alternative?

From: Sam Partington (sam.partington_at_[hidden])
Date: 2003-11-25 11:17:57

Peter Dimov <mailto:pdimov_at_[hidden]> wrote:
> Sam Partington wrote:
>> 
>> Documentation of Peters idiom in a very limited form, including why
>> it is not suitable in a generic case is available in the rationale
>> part of the bool_testable notes : 
>> 
>> 
> http://boost-consulting.com/boost/libs/utility/operators.htm#s
> afe_bool_note 
> 
> I'm not sure whether the statement "this implementation required the
> user to provide operator!" is correct. Operator! in shared_ptr is a
> Borland-specific workaround.

Its not incorrect in what it meant to say, though it is perhaps badly
phrased.  If I rephrase it to something like :

"in the safe-bool implementation that was suggested, the user would provide
operator! and a operator bool-like conversion is provided by the library.
In contrast, the implementation of bool_testable that was decided upon, the
user provides operator bool, and the library makes this safe, and provides
operator!"

I.e. the sentence was referring to the particular implementation of the
safe-bool idiom that was suggested for bool_testable.  Not for the safe-bool
idiom as a whole.

Sam

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