Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!milano!cadillac!puma!vaughan
From: vaughan@puma.cad.mcc.com (Paul Vaughan)
Newsgroups: comp.lang.c++
Subject: class member declarations
Message-ID: <8546@cadillac.CAD.MCC.COM>
Date: 25 May 90 20:30:11 GMT
Sender: news@cadillac.CAD.MCC.COM
Lines: 51



A long time back I proposed that declaration capability like the
following example be supported:

class Foo;
void Foo::bar(int);

void baz(Foo* f) { f->bar(3); }

where to link a program with this fragment, there must exist a class
declaration

class Foo . . . {
public:
  . . .
  void bar(int);
. . .
};

I believe that it could be easily implemented without imposing
constraints on the linker, simply by generating and using symbols for
the offsets required for generating code with appropriately munged
unique and constructable names.  However, this does not exist in C++.

Now I have an application that routinely does interactive compilation,
but which suffers performance difficulties because of the amount of
material that must be included whenever I use a class.  In particular,
I must include the class definitions for not only Foo, but everything
in Foo's inheritance graph, and everything in the inheritance graphs
of every class of which Foo objects have a member, and so on.  Since
all the information about a class and transitively related classes,
except for the actual code in the function members, must be included
for any code module that uses a member of a class, I claim that C++ is
EXTRAORDINARILY NON-MODULAR.

It's no wonder why people talk about the preprocessed version of a
source module being 50 times longer than the code file.  Fifty times
is conservative--it could be proportional to the size of an entire
application compared to the size of an individual code module.
There's no way to avoid it.

For my application, I'm considering a royal kludge of declaring a lot
of non-class-member functions with self munged names to get around
this problem.  Can you say "DEATH OF OBJECT ORIENTATION?"




 Paul Vaughan, MCC CAD Program | ARPA: vaughan@mcc.com | Phone: [512] 338-3639
 Box 200195, Austin, TX 78720  | UUCP: ...!cs.utexas.edu!milano!cadillac!vaughan