Re: Fun with member-function pointers

From	"Default User" <defaultuserbr@yahoo.com>
Newsgroups	comp.lang.c++
Subject	Re: Fun with member-function pointers
Date	2011-08-22 19:06 -0500
Message-ID	<9bg98kFlfoU1@mid.individual.net> (permalink)
References	<9bg0ojFsapU1@mid.individual.net> <j2uoi5$jgn$1@dont-email.me>

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"Victor Bazarov" <v.bazarov@comcast.invalid> wrote in message 
news:j2uoi5$jgn$1@dont-email.me...
> On 8/22/2011 5:41 PM, Default User wrote:
> I'd probably tried to change this to
>
>     CALL_HANDLER(o, p, args) ((o).*(p)) args

What! You dare question the CLC++ FAQ list where I copied that from? I'll 
look at it.

> (see below for the use).
>
>>
>> class tbase
>> {
>> public:
>>     tbase() : p(0)
>
> Perhaps (a) it shouldn't be public (do you intend to instantiate this? 
> It's an ABC, isn't it?) and (b) it should have the argument to init the 
> 'p' with (defautl to 0):

This was just a quicky demo. So I didn't bother with some of that sort of 
thing. I'll check the "real" code though.

>> class test : tbase
>> {
>> public:
>>     test()
>>     {
>>        p  = static_cast<HandlerPtr>(&test::f);
>
> Shouldn't you use the initializer list instead of the assignment?  See 
> FAQ.

For this case, sure. But the actual code will be putting them in a std::map 
with the op codes as indexes.

> There is no real problem yet.  Now imagine that somebody thinks of 
> deriving from your 'test' and providing their own handler?  How would they 
> do it?  Or can that never happen?

I guess I'm not sure what the specific problem you're concerned about. I 
fear my quicky proof-of-concept demo might have been too sketchy.

> Another possible solution is to actually have a pointer to function 
> instead of pointer to member, and cast 'this' to the specific class, which 
> is usually "safer", I think.  Not that I know much about that...

I don't think so. One goal is to push a lot of behavior down to the base 
class. I can make the handler map and the handler calling function go down 
there. Then the derived class will populate the map with its specific 
handler for each op code. The upper level modules just call with the op 
codes and data.

I'll look to see if I can rework my demo tomorrow to make it a bit more like 
the real use case.

Brian

Thread

Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-22 16:41 -0500
  Re: Fun with member-function pointers Victor Bazarov <v.bazarov@comcast.invalid> - 2011-08-22 19:25 -0400
    Re: Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-22 19:06 -0500
  Re: Fun with member-function pointers Juha Nieminen <nospam@thanks.invalid> - 2011-08-23 07:09 +0000
    Re: Fun with member-function pointers Victor Bazarov <v.bazarov@comcast.invalid> - 2011-08-23 08:04 -0400
      Re: Fun with member-function pointers Juha Nieminen <nospam@thanks.invalid> - 2011-08-23 13:34 +0000
        Re: Fun with member-function pointers Victor Bazarov <v.bazarov@comcast.invalid> - 2011-08-23 13:02 -0400
      Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 19:12 -0700
    Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 18:51 -0700
  Re: Fun with member-function pointers Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-08-23 09:07 +0200
    Re: Fun with member-function pointers Juha Nieminen <nospam@thanks.invalid> - 2011-08-23 10:09 +0000
      Re: Fun with member-function pointers Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-08-23 15:04 +0200
    Re: Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-23 10:36 -0500
      Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 18:46 -0700
        Re: Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-24 09:33 -0500
          Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-24 08:32 -0700
            Re: Fun with member-function pointers "Default User" <defaultuserbr@yahoo.com> - 2011-08-24 11:15 -0500
              Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-24 09:30 -0700
      Re: Fun with member-function pointers Marcel Müller <news.5.maazl@spamgourmet.com> - 2011-08-24 12:27 +0200
        Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-24 06:46 -0700
          Re: Fun with member-function pointers Marcel Müller <news.5.maazl@spamgourmet.org> - 2011-08-24 18:57 +0200
            Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-24 13:08 -0700
              Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-24 13:44 -0700
                Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-25 04:23 -0700
                Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-25 07:31 -0700
                Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-25 08:21 -0700
                Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-25 10:50 -0700
                Re: Fun with member-function pointers Leigh Johnston <leigh@i42.co.uk> - 2011-08-25 13:57 +0100
                Re: Fun with member-function pointers Leigh Johnston <leigh@i42.co.uk> - 2011-08-25 14:08 +0100
                Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-25 07:32 -0700
                Re: Fun with member-function pointers Leigh Johnston <leigh@i42.co.uk> - 2011-08-25 15:45 +0100
                Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-25 07:48 -0700
    Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 18:43 -0700
  Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-23 03:49 -0700
    Re: Fun with member-function pointers Paul <pchristor@yahoo.co.uk> - 2011-08-23 06:44 -0700
  Re: Fun with member-function pointers Andrey Tarasevich <andreytarasevich@hotmail.com> - 2011-08-23 18:28 -0700
  Re: Fun with member-function pointers Jeff Flinn <TriumphSprint2000@hotmail.com> - 2011-08-25 11:29 -0400

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