Re: [boost] [Fit] formal review starts today

5 Mar 2016


      Le 05/03/2016 17:11, Paul Fultz II a écrit :
...
On Saturday, March 5, 2016 at 6:40:49 AM UTC-6, Vicente J. Botet 
Escriba wrote:
Le 05/03/2016 13:22, Peter Dimov a écrit :
    > Rob Stewart wrote:
    >> On March 4, 2016 3:27:08 PM EST, Paul Fultz II
    javascript:>
    >> wrote:
    >> >
    >> > The library could switch to using `Callable`, if everyone feels
    >> that is > better. However, I honestly prefer to make mutable
    >> explicit. I would > like to hear feedback from other reviewers
    as well.
    >
    > I do not object to your requiring ConstCallable. I made
    > boost/std::bind const-neutral because this felt the right thing
    to do
    > - it's not bind's job to tell you what your function object
    ought to
    > do, it just reflects whatever it does. At the same time, stateful
    > function objects do have limited applicability outside of for_each
    > which specifically guarantees order and returns the function
    object.
    > You could pass bind( ++_1, 0 ) to generate_n and that's pretty
    much it.
    >
    > So I do not see the requirement as a defect warranting
    rejection. If
    > users demand Callable support, you'll add it. If not, not.
    >
    >> If your library only requires Callable, then users can supply a
    >> Callable or a ConstCallable. When you require a ConstCallable,
    they
    >> cannot supply a Callable. There may be valid reasons for that
    >> restriction in certain cases, but they should be documented rather
    >> than just imposed as a convention.
    >
    > That's true in principle. In practice though function objects
    that are
    > not ConstCallable are in 90% of the cases the result of a forgotten
    > 'const' on operator() and not a deliberate decision. So requiring
    > ConstCallable catches errors.
    >
    For me the question is if the functions provided by the library need
    that the function object must be const or not.
They do not need it. However, there can be some unexpected behavior 
when the
user uses mutable function objects, because the functions can be copied or
moved multiple times.
Copied or moved? Does the library accepts move only function objects?
Do you have an example of unexpected behavior?

Vicente

Re: [boost] [Fit] formal review starts today

Vicente J. Botet Escriba