Re: Maintaining stack semantics but using polymorphic code

From:

=?ISO-8859-1?Q?Daniel_Kr=FCgler?= <daniel.kruegler@googlemail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Wed, 18 Apr 2012 09:52:11 -0700 (PDT)

Message-ID:

<jmmc7p$h2m$1@dont-email.me>

On 2012-04-18 13:57, asif.lse wrote:

I want to specify only ONE return type in this function.

What do you precisely mean by "this" function?

I suspect I could auto here and use decltype to declare a pointer to
the returned type so that I could assign that pointer/ref to a
pointer/ref to an abstract class for polymorphic access. I haven't
read up much on these new C++ features but could somebody help me
here? I want to use stack variables and yet want to execute
polymorphic code. The problem is that I have to specify the concrete
class name and return type. So, apparently, there is no
polymorphism. I am just thinking off the top of my head but I feel
that this is very doable. Can I use templates here?

You should think about keeping the polymorphic behaviour *within* the
return type. std::shared_ptr is similar, because the dynamic
polymorphism is still provided by the contained object. Think of it as
some form of adapter technique. Other examples with similar
characteristics are std::function: The function call expression is
potentially polymorphic, depending on the provided callable object.

HTH & Greetings from Bremen,

Daniel Kr?gler

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