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

Subject: Re: [boost] [Fit] formal review starts today
From: Paul Fultz II (pfultz2_at_[hidden])
Date: 2016-03-05 11:11:04

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 <pfu..._at_[hidden] 
> <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.
 

>
> Vicente 
>
> _______________________________________________ 
> Unsubscribe & other changes: 
> http://lists.boost.org/mailman/listinfo.cgi/boost 
>