Re: [boost] very simple implementation of Andrei Alexandrescu's ScopeGuard idiom

Subject: Re: [boost] very simple implementation of Andrei Alexandrescu's ScopeGuard idiom
From: Lorenzo Caminiti (lorcaminiti_at_[hidden])
Date: 2012-09-04 11:27:15

On Tue, Sep 4, 2012 at 5:08 AM, Alexander Stoyan
<alexander.stoyan_at_[hidden]> wrote:
> Hi folks,
> In contrast to BOOST_SCOPE_EXIT there is a much shorter and less verbose
> implementation that is especially good with c++11 lambda usage -
> http://alexander-stoyan.blogspot.com/2012/02/scope-exit-handlers.html

Looks the same as the one suggested in Boost.ScopeExit docs:
http://www.boost.org/doc/libs/1_51_0/libs/scope_exit/doc/html/scope_exit/alternatives.html#scope_exit.alternatives.c__11_lambdas

> -----Original Message-----
> From: boost-bounces_at_[hidden] [mailto:boost-bounces_at_[hidden]]
> On Behalf Of Stewart, Robert
> Sent: Tuesday, September 04, 2012 3:01 PM
> To: boost_at_[hidden]
> Subject: Re: [boost] very simple implementation of Andrei Alexandrescu's
> ScopeGuard idiom
>
> Sergey Radionov wrote:
>> 2012/9/4 Stewart, Robert <Robert.Stewart_at_[hidden]>:
>> > Sergey Radionov wrote:
>> >>
>> >>
> <https://github.com/RSATom/finally_execute/blob/master/finally_execute.h>
>> >>
>> >> based on
> <http://www.drdobbs.com/cpp/generic-change-the-way-you-write-excepti/1844037
> 58?pgno=2>
>> >>
>> >> I know about <http://sourceforge.net/projects/loki-lib/> but
>> >> with boost::bind this can be much simpler:
>> >>
>> >> <https://github.com/RSATom/finally_execute/blob/master/README>
>> >>
>> >> I've used this in many of my projects, and found it very
>> >> usefull....
>> >>
>> >> don't understand, why this simple solution does not
>> >> contributed already to Boost by someone else... :)
>> >
>> > I created a version, too, but the usage is much simpler.
>> >
>> > Given the following:
>> >
>> > FILE * const file(fopen("test", "r"));
>> > if (file)
>> > {
>> >    // A
>> > }
>> >
>> > Your usage, at A, is:
>> >
>> >    finally_execute _(make_fin_exec(
>> >       boost::bind(fclose, file)));
>> >
>> > Mine is:
>> >
>> >    scope_guard _(fclose, file);
>> >
>> > As you can see, a little more complication in the component
>> > makes usage much simpler.
>>
>> In this case, I think, much simple usage gives less clear
>> code, since people reading code will see boost::bind and
>> understand what it mean.
>> With your version, he maybe should have to a look to help or
>> header...
>
> Objectively, your version requires knowing how to use
> boost::bind, which arguably is a good thing, and requires calling
> a function template, both of which make the statement more
> verbose.  My version uses the same calling convention as, say,
> boost::thread: pass the function object and the arguments it
> requires.  It even accepts a std::tr1::function<void()> so you
> can bind to your heart's content.
>
> As for the concern that one must read help or a header to
> understand how to use scope_guard, surely you jest.  One cannot
> understand finally_execute or make_fin_exec() without doing
> likewise.  You simply construct an instance of scope_guard with
> the function object to call, and any required arguments.  What
> could be simpler?
>
>> > There's also Boost.Scope Exit, though it's even more
>> > verbose:
> [snip unreferenced content]
>> > Rob Stewart
> [snip my signature block]
>> > IMPORTANT: The information contained in this email and/or
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>
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--Lorenzo