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Subject: Re: [boost] [property] interest in C# like properties for C++?
From: Edward Diener (eldiener_at_[hidden])
Date: 2009-10-22 19:30:02

Olaf van der Spek wrote:
> On Thu, Oct 22, 2009 at 9:54 PM, vicente.botet <vicente.botet_at_[hidden]> wrote:
>> Don't forget, public is public, so part of the contract.
> Not everything that compiles is legal or defined behaviour.
> I'd love to see proper properties support, but I'm afraid that
> requires language support, otherwise you can't support reference
> properties.

Of course you can support reference properties along with value
properties. It is just very hard, if not impossible, to support both
kinds using the same template class. So really one would not a separate
template class to support reference properties.

Manipulating a reference property would be done purely through accessing
the property. Accessing a reference property returns a T & or a T const
& depending on whether the property is const or not. In the case where a
T & is returned the reference property is read/write if T itself is not
const, since you can manipulate T through the reference, whereas in the
case where T const & is returned ( or where T & is returns but T is
itself const), the reference property is read only.

But one certainly does not need language support for this. In fact
reference properties are very useful for user-defined types as T since
the T & ( or T const & )'s data should ideally be manipulated for a T
user-defined type through properties within T itself. Thus the property
concept can drill down, so to speak, when the T itself is a user-defined
type with is own properties.

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