Re: [boost] Review: Function library

From: Peter Dimov (pdimov_at_[hidden])
Date: 2001-06-08 11:00:19

From: "Douglas Gregor" <gregod_at_[hidden]>

> > FWIW, I tend to agree with Darin that the if(f), f = nil, f == nil
> > constructs, while useful, are not strictly necessary (considering the
> > problems they introduce) - the explicit empty(), clear() methods are
fine.
>
> Which problems do they introduce? Unless there are serious problems with
the
> nil/null type (such that it won't be adopted), I'm not sure I see any
further
> problems with the operators.

The implicit conversion is quite dangerous. It enables code like this:

boost::function<void> f;

f + 4;
f - f;

to compile. I'd expect comparisons of the form f < f, f > f, etc to also
work, but some compilers (Intel, MSVC) don't agree with me on this; g++
2.95.2 and bcc32 5.5.1 do.

As for the f = nil syntax... I do prefer the f = 0; syntax when f is a smart
pointer; however, f = nil and f.clear() are equal to me. Neither is an
idiom.

--
Peter Dimov
Multi Media Ltd.