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From: r91400@memqa.uucp (Michael C. Grant)
Newsgroups: comp.object,comp.lang.c++
Subject: Re: Choice of language for manufacturing Applications
Message-ID: <5043@memqa.uucp>
Date: 8 Aug 90 10:20:58 GMT
References: <26686@pasteur.Berkeley.EDU> <56343@microsoft.UUCP>
Organization: Memory R&QA, Motorola SPD
Lines: 26


 In article <26686@pasteur.Berkeley.EDU> lozinski@argon.UUCP (Chris Lozinski) writes:
>
> Technically this is caused by the default
>structures of the objective-C language where the target class of a
>message does not need to be known at compile time.  In contrast the
>default in C++ is that the target class does need to be known at
>compile time.

No, that is not necessarily true.  If you define a 'base' or 'mother'
class for all classes with common methods, then any program statement
that needs to call that common method need not know the target class at all.

As a simple example, I have a base class 'BaseObject' that I use a lot.
Its only instance variable is 'NumRefs', which gives a count of how many
lists the object is contained in (so I don't ~X it more than once!)
But, it also contains a 'PrintOut' method which I then override in every
other class I define.  So, if I call
	I_Dont_Know_What_Class_This_Is->PrintOut(),
it will work for any object use.  This line of code could be in a procedure
call that accept any BaseObject subclass.

Defining a mother class like this could really help the organization of the
program, anyway.

Michael C. Grant