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From: Struan.Judd@sunbrk.FidoNet.Org (Struan Judd)
Newsgroups: comp.lang.c++
Subject: Re: Proposal: 'virtual' class members for C++
Message-ID: <675518012.34@sunbrk.FidoNet>
Date: 28 May 91 04:12:39 GMT
Sender: Usenet@sunbrk.FidoNet.Org
Lines: 55

Reply-To: struan@fivegl (Struan Judd)

In article <1991May24.170014.17301@kestrel.edu> gyro@kestrel.edu (Scott Layson Burson) writes:
>In article <1745@culhua.prg.ox.ac.uk> bill@robots.oxford.ac.uk (Bill Triggs) writes:
>>I would like to propose a simple extension of C++ syntax
>>which would allow 'soft' or 'virtual' class members to be
>>simulated by member functions.
>>
>>[...]
>
>I like the basic idea of having things that look like member variables
>that are actually member function invocations.  However, I don't like
>
>[...]
>
>-- Scott
>Gyro@Reasoning.COM

Throwing my $0.02 into the ring on this general subject,  I quite like
    using the following style.  While it does not hide the fact that
    assignments to variables are being done through a function interface,
    it does allow non-friends of the class 'access' to some of the member
    variables of the class.

Example:

class Scr_Location {
    private:
	unsigned char SL_Left, SL_Top, SL_Right, SL_Bottom;
    public:
	Scr_Location(void);
	.
	.
	.
	const unsigned char &Left = SL_Left, &Right = SL_Right,
			    &Top = SL_Top, &Bottom = SL_Bottom;
	.
	.
	.
};

(Question:  It would be very nice if C++ compilers could recognise
    this construct and not actually reserve storage in the class
    instances for the references.  Do any do this?)

This works for me as I tend to only have code executed when variable
    values are changed not when they are merely obtained.

-- 
+------------------------------------------------+---------------------+
| Struan L. Judd                                 | struan@fivegl.co.nz |
| Of all the bit boxes in this electronic world, | PH:  +64 9 302-1621 |
| this message had to shift into this one.       | FAX: +64 9 302-1617 |

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