Re: How can I remove dynamic_cast and if statements from this code snippet?

From	Bart v Ingen Schenau <bart@ingen.ddns.info>
Newsgroups	comp.lang.c++
Subject	Re: How can I remove dynamic_cast and if statements from this code snippet?
Date	2011-11-18 14:45 +0100
Organization	No organisation in particular
Message-ID	<ja5nie$9f2$1@localhost.localdomain> (permalink)
References	<f5bb1b81-4daf-4b54-b7f2-d601f03ab1a2@y42g2000yqh.googlegroups.com> <af7094e6-fbc9-4bed-b9c7-c1c4ad9d6841@w7g2000yqc.googlegroups.com>

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Werner Wrote:

> On Nov 18, 12:09 am, Chris Stankevitz <chrisstankev...@gmail.com>
> wrote:
> > On Nov 17, 11:21 am, <address...@invalid.invalid> wrote:
> >
> > > I think this is a typical usecase for the "visitor"pattern:
> >
> > Tobi, this is exactly what I was looking for.  Case closed.
> 
> What happens when new shapes are added to the hierarchy?

Then the ShapeVisitor and derived visitors must be extended to support the
new shape.
This is no different from the original code with an if-else ladder based on
the result from dynamic_cast, except that the compiler is better able to
help warn you if you forgot to update a visitor.

> 
> Kind regards,
> 
> Werner

Bart v Ingen Schenau

Thread

How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-16 10:37 -0800
  Re: How can I remove dynamic_cast and if statements from this code snippet? Ian Collins <ian-news@hotmail.com> - 2011-11-17 07:52 +1300
    Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-16 11:14 -0800
      Re: How can I remove dynamic_cast and if statements from this code snippet? red floyd <no.spam.here@its.invalid> - 2011-11-16 12:03 -0800
        Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-16 13:28 -0800
          Re: How can I remove dynamic_cast and if statements from this code snippet? Leigh Johnston <leigh@i42.co.uk> - 2011-11-16 21:39 +0000
            Re: How can I remove dynamic_cast and if statements from this code snippet? Leigh Johnston <leigh@i42.co.uk> - 2011-11-16 21:40 +0000
              Re: How can I remove dynamic_cast and if statements from this code snippet? Leigh Johnston <leigh@i42.co.uk> - 2011-11-16 21:43 +0000
                Re: How can I remove dynamic_cast and if statements from this code snippet? Leigh Johnston <leigh@i42.co.uk> - 2011-11-16 21:45 +0000
            Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-16 13:46 -0800
              Re: How can I remove dynamic_cast and if statements from this code snippet? Leigh Johnston <leigh@i42.co.uk> - 2011-11-16 21:49 +0000
      Re: How can I remove dynamic_cast and if statements from this code snippet? Leigh Johnston <leigh@i42.co.uk> - 2011-11-16 20:35 +0000
        Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-16 13:38 -0800
      Re: How can I remove dynamic_cast and if statements from this code snippet? Ian Collins <ian-news@hotmail.com> - 2011-11-17 10:37 +1300
        Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-16 13:41 -0800
          Re: How can I remove dynamic_cast and if statements from this code snippet? Ian Collins <ian-news@hotmail.com> - 2011-11-17 10:56 +1300
            Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-16 14:03 -0800
              Re: How can I remove dynamic_cast and if statements from this code snippet? Ian Collins <ian-news@hotmail.com> - 2011-11-17 11:12 +1300
                Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-16 15:20 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Werner <werasm@gmail.com> - 2011-11-16 23:39 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Goran <goran.pusic@gmail.com> - 2011-11-17 05:42 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-17 10:37 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Werner <werasm@gmail.com> - 2011-11-17 23:23 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Goran <goran.pusic@gmail.com> - 2011-11-18 01:46 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Goran <goran.pusic@gmail.com> - 2011-11-18 01:25 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Werner <werasm@gmail.com> - 2011-11-17 23:28 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-17 10:27 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Goran <goran.pusic@gmail.com> - 2011-11-17 05:17 -0800
                Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-17 10:35 -0800
  Re: How can I remove dynamic_cast and if statements from this code snippet? Francesco <xtrigger303@gmail.com> - 2011-11-17 01:56 -0800
    Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-17 10:31 -0800
  Re: How can I remove dynamic_cast and if statements from this code snippet? <address_is@invalid.invalid> - 2011-11-17 19:21 +0000
    Re: How can I remove dynamic_cast and if statements from this code snippet? Leigh Johnston <leigh@i42.co.uk> - 2011-11-17 19:33 +0000
    Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-17 14:09 -0800
      Re: How can I remove dynamic_cast and if statements from this code snippet? Werner <werasm@gmail.com> - 2011-11-17 23:30 -0800
        Re: How can I remove dynamic_cast and if statements from this code snippet? Bart v Ingen Schenau <bart@ingen.ddns.info> - 2011-11-18 14:45 +0100
    Re: How can I remove dynamic_cast and if statements from this code snippet? Goran <goran.pusic@gmail.com> - 2011-11-18 02:58 -0800
      Re: How can I remove dynamic_cast and if statements from this code snippet? Tobias Müller <troplin@bluewin.ch> - 2011-11-18 16:56 +0000
        Re: How can I remove dynamic_cast and if statements from this code snippet? Chris Stankevitz <chrisstankevitz@gmail.com> - 2011-11-18 17:27 -0800
    Re: How can I remove dynamic_cast and if statements from this code snippet? Goran <goran.pusic@gmail.com> - 2011-11-18 01:29 -0800
  Re: How can I remove dynamic_cast and if statements from this code snippet? Noah Roberts <roberts.noah@gmail.com> - 2011-11-18 09:23 -0800

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